UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


THE 

CHEMISTRY  AND  METALLURGY 

OP 

C  OPPER, 

INCLUDING  A_DESCRIPTION  OF   THE  PRINCIPAL  COPPER   MINES  OF  THE 
UNITED  STATES  AND  OTHER  COUNTRIES, 

THE  ART  OF  MINING  AND  PREPARING  ORES  FOR  MARKET, 

AND   THE 

Various  graces  of  fljjoppur  £mdtm#,  &c., 

BY 

A.   SNOWDEN  PIGGOT,  M.  D., 

ANALYTICAL   AND   CONSULTING  CHEMIST,   MEMBER  OF   THE  AMERICAN    ASSOCIATION   FOE 

THE  ADVANCEMENT  OF  SCIENCE,  OF  THE  AMERICAN  MEDICAL  ASSOCIATION, 

AUTHOR  OF  DENTAL  CHEMISTRY  AND  METALLURGY,  4C.  4C. 


WITH     ILLUSTRATIONS. 


PHILADELPHIA: 
LINDSAY    AND    BLAKISTON, 

"1858 


8834     5 


Entered  according  to  the  Act  of  Congress,  in  the  year  1858,  by 
LINDSAY  AND  BLAKISTON, 

in  the  clerk's  office  of  the  District  Court  for  the  Eastern  District  of 
Pennsylvania. 


BHRT  B.  ASHMKAD,  BOOK  AHD  JOB  PRIHTEI 
George  Street  above  Eleventh. 


TH 
ISO 


CAMPBELL   MORFIT,   M.  D.,   CHEMIST, 

THIS     WORK     IS     INSCRIBED 

BY    HIS    PBIBND, 

THE   AUTHOR. 


PREFACE. 


Having  been  engaged  for  some  years  in  the  analysis  of  ores 
of  copper,  and  in  the  determination  of  chemical  questions  con- 
cerning that  metal,  in  connection  with  a  large  and  well-ap- 
pointed smelting  establishment,  the  author  has  acquired  ex- 
perience which  he  has  thought  might  be  of  service  to  others 
engaged  in  the  same  pursuit.  He  has  also  been  led  to  believe 
that  some  information,  in  a  form  accessible  to  the  masses  of 
our  people,  on  the  subject  of  mines,  veins  and  ores  of  copper, 
with  the  known  laws  of  their  occurrence,  might  be  of  service 
in  assisting  in  the  development  of  this  very  important  part  of 
the  mineral  wealth  of  our  country. 

The  present  work  is  designed  to  supply  what  the  author  be- 
lieves to  be  a  desideratum.  His  aim  has  been  to  popularize 
it  sufficiently  for  the  use  of  those  who  have  not  hitherto  made 
the  sciences  of  chemistry  and  geology  a  special  study,  with- 
out so  neglecting  details  as  to  render  it  of  no  value  to  the  ex- 
pert in  these  studies.  How  far  he  has  succeeded  in  this  at- 
tempt is  for  the  public  to  judge. 

In  the  chapter  on  Mining,  the  author  has  endeavored  to 
present  as  complete  an  account  of  the  various  copper  regions, 

i* 


yi  PREFACE. 

as  was  possible  in  the  limited  space  of  a  volume  like  the  pres- 
ent. In  treating  of  foreign  mines,  it  has  not  been  intended 
to  give  anything  like  a  minute  description  of  them,  but  simply 
to  present  to  the  reader  a  sketch  of  their  geology  and  general 
results,  sufficient  for  the  purposes  of  comparison  with  our  own 
mining  regions.  In  reference  to  the  mines  of  the  United 
States  the  author  would  say,  that  he  has  endeavored  to  em- 
body the  latest  information  accessible  to  him.  Those  who 
have  attempted  to  collect  similar  statistics,  are  aware  of  the 
difficulty  of  obtaining  reliable  information,  and  will  pardon 
any  omissions  they  may  detect. 

In  the  chapters  on  Smelting  and  Assay  of  Ores,  the  object 
has  been  to  define  the  principles  on  which  the  processes  are 
based,  and  to  describe  with  clearness  and  precision,  the  various 
methods  by  which  the  results  are  proposed  to  be  attained.  It 
is  to  be  hoped,  that  in  this,  as  in  the  other  departments  treat- 
ed upon,  the  work  will  be  found  sufficiently  full  and  accurate 
to  serve  as  a  guide  to  those  engaged  in  adding  to  the  world's 
production  of  copper. 

A.  SXOWDEN  PIGGOT. 


40  BOLTOX  STREET,  BALTIMORE, 
January  20th,  1858. 


TABLE    OF    CONTENTS. 


CHAPTER    I. 

CHEMICAL  RELATIONS  OF  COPPER, 25 


CHAPTER    II. 

ORES  OF  COPPER, 68 


CHAPTER    III. 

ANALYSIS  OF  COPPER  ORES,  .       .      90 


CHAPTER    IV. 

MINES  AND  MINING,    .  .    143 


CHAPTER    V. 

MINES  OF  COPPER, 193 


L- 


viii  TABLE   OF   CONTENTS. 

CHAPTER    VI. 
COPPER  SMELTING, 286 


CHAPTER    VII. 

ALLOYS  OF  COPPEE, 349 


APPENDIX, 380 


ERRATUM. 
Page  215,  2d  and  3d  lines  from  top,  "  Cope''1  should  read  "Cobre." 


INDEX 


PAGE 

Acetates  of  Copper      -  61 

Basic          -  -         62 

Bibasic       -  63 

Hyperbasic  -  -        ib. 

Neutral      -  -  61,66 

Sesquibasic  -  -  -         63 

Tribasic     -  ib. 

Adit  level         -  -       173 

Adventure  Mining  Company     -  -       247 

Agate  Harbor  Mining  Company  ....       229 

Albion  Mining  Company  -  ...       243 

Alloys  of  Copper          -  -  -  -       349 

America,  production  of  -  384 

Ammonia-sulphates  of  Copper  -  -  -  57 

Ammoniated  Copper    ------        ib. 

Amphid  salts   -------48 

Ann  Phipps  Mine         -  -  -  -  -  -270 

Antimony,  detection  of,  in  copper  ores  -  96 

Aphanesite       -  89 

Arcot  -  357 

Arsenic,  detection  of,  in  copper  ores    -  -  -  -        96 

Arsenites  of  Copper     -  -  -         63 

Atacamite        -  -----         73 

Aurichalcum    -  -  -  -  -  -  -351 

Aztec  Mining  Company  -       247 

Azurite  -------85 


INDEX. 


PAGE 

Bare  Hill  Mine 

265 

Barnhardtite     -             - 

78 

Barrel  work     -            - 

227 

Basalt 

-       147 

Bath  metal 

355 

Bearing            - 

-       157 

Bell  metal        -            ... 

-       373 

Binoxide  of  copper       - 

39 

Black  oxide  of  copper  - 

72 

Blistered  copper 

325 

Blue  metal       - 

317 

vitriol      - 

-  51,87 

Bohemian  Mining  Company     - 

-       247 

Borate  of  copper 

60 

Boro-fluoride  of  copper 

47 

Bournonite       - 

83 

Brass  -                                      - 

-       350 

Bristol    - 

-       355 

solder    .... 

-       356 

Bridgewater  Mine 

-       282 

Bristol  Mine     -            ... 

-       258 

Brochantite      -            ... 

87 

Bromate  of  copper        ... 

61 

Bromide  of  copper        - 

46 

Bronze             - 

355 

Bruce  mine      -            ... 

-       254 

Brunswick  green          - 

45 

Burra-Burra  Mine        - 

208 

Calcination,  chemistry  of         - 

296 

Calciner 

Cannon  metal  - 

-       371 

Canton  Mine    - 

-       279 

Cantonite         -            ... 

76 

Carbonates  of  copper  - 

60 

Chalcotrichite               - 

71 

Chemical  relations  of  copper    - 

25 

INDEX.  xi 

PAGE 

Chlorate  of  copper        -                                       -  -             -  61 

Chloride  of  copper        ------  44 

and  ammonium       -            -  -            -  46 

potassium  -----  ib. 

hydrated     -             -  -  45 

Chrysocolla  (alloy)       -  -            353,  355 

(ore)           - 84 

Clarendon  consols        -  -            -  213 

Clark  Mining  Company  -  229 

Cliff  Mine         -  -  237 

Coarse  metal    -  -  303 

Cobre  Mines     -  -  215 

Cocheco  Mine  -  -  279 

Condurrite        -                                         -             -  -             -  81 

Connellite        -  -  87 

Consolidated  Mines      -  -  209 

Contra  lodes     -             -             -             -            -  -             -165 

Copper,  action  of  atmosphere  on          -            -  -  30 

antiquity  of  manufacture  of    -  -  25 

application  of  to  analysis         -  -  29 

assay  of  -  123 

by  dry  way,  apparatus  for       -  -            -  123 

of  ores  of  first  class  -            -  125 

second  class  -            -  129 

third  class  -            -  138 

fourth  class  -             -  139 

roasting  in           -  -  131 

with  cyanide  of  potassium  -  136 

nitre  -  ib. 

by  humid  process        -  137 

Rivofs  plan  -  138 

chemical  characters  of                          -  -    '         -  26 

commercial      -             -             -             -  -             -28 

purification  of      -  -  29 

cupellation  of               -  139 

detection  of,  in  ores     -            -  -  92 

determination  of,  by  caustic  potash     -  -  102 

metallic  iron         -  -             -  105 


Xll  INDEX. 

PAGE 

Copper,  determination  of,  by  metallic  zinc        -                          -  106 

sulphureted  hydrogen      -  109 

Cassaseca's  method          -             -  109 

Level's  method    -            -            -  107 

Pelouze's  method                          -  109 

estimation  of  -             -             -             -             -             -  102 

etymology  of-  -  -  -  -  -25 

fusion  point  of  -  -  -  -  -27 

glance              _-._._  74 

method  of  obtaining  it  pure     -                                         -  29 

native               -             -             -             -             -  68 

ores,  qualitative  analysis  of     -             -             -             -  93 

quantitative  analysis  of  -                                         -  102 

smelting  of                                                                 -  286 

oxidation  of    -  -  -  -  -  -  30, 33 

facilitated  by  fat  -                                         -  31 

recovery  from  alloys   -                                                       -  378 
separation  from  antimony,  arsenic,  tin,  platinum,  gold, 

iridium,  &c.             -             -  122 

bismuth          -             -                           -  112 

cadmium        -             -             -             -  116 

cobalt,  nickel,  zinc,  iron,  manganese,  117 

Berthier'g  method  120 

gold  -                          -                          -  121 

lead   -  113 

mercury          -             -             -             -  115 

nickel  and  zinc,  Flajolot's  plan           -  119 

silver                           -                          -  114 

zinc,  Hautefeuille's  plan          -             -  121 

specific  gravity  of        -            -                         -            -  27 

uses  of             ------  68 

volatilization  of           -                           -                           -  28 

Copper  Falls  Mining  Company              -  229 
Cornwall,  geology  of-             -             -             -             -             -194 

production  of                                       -  382 

Covelline          -                                                    _            _            -  76 

Cranberry  Mine             --_.-_  269 

Cross  courses  -------  157 


INDEX.  Xlll 

PAGE 

Cuba,  production  of    - 

Cupric  acid      -------84 

DaltonMine     -  -  271 

Devon  consols  -  200 

Digenite            -  -76 

Diniodide  of  copper      -  -  47 

Dioptase           -  -  84 

Dolcoath  Mine  -  200 

Dolly  Hide  Mine           -  -  262 

Domeykite       -             -            -  -             -             -             -81 

Douglass  Houghton  Mine          -  -             -  246 

Drift  -  -  177 

Dutch  foil        -  -  355 

Eagle  Harbor  Mining  Company  -  229 

Erinite  -  89 

Erubescite        -  -  77 

Euchroite          -  -  88 

Fahlerz  -  81 

Flemington  Mine           -  -  282 

Fluckan  -  197 

Foot  wall         -  -  157 

Franklin  Mine  -  282 

Fulton  Mining  Company            -  -  243 

Furnace  for  smelting   ------  300 

Gangue  -  161 

Gap  Mine         -  -  261 

German  chest  -  -  188 

silver  -  358 

Gilding  metal  -  352,  355 

Gneiss  -            -  147 

Gold,  detection  of,  in  copper  ores  -                                       -  92 

Gossan             -  -            -  171 

Granite             -            -  -  147 

Gray  copper     -  -                          -  81 

Great  Britain,  production  of   -  -  384 

2 


XIV  INDEX. 

PAGE 

Green  candies  poisonous          -  67 

Hade   -  -  157 

Hanging  wall  -  -  ib. 

Hard  metal      -  -  316 

Harrisite           -  -75 

Hiwasse  Mine  -  277 

Horse  -  -  162 

Hydride  of  copper        -  -  40 

Hyposulphate  of  copper  -  58 

Hyposulphite  of  suboxide  of  copper  -                                       -  49 

Hyposulpkophosphite  of  copper  -  67 

Indigo  copper  -  -  76 

Iron  City  Mining  Company       -  234 

Isabella  Mine  -  -  278 

Isle  Royale,  geology  of             -  -                          -  243 

Kapunda  Mine  -  209 

Keweenaw  Point,  geology  of   -  -  223 

Mining  Company  -                                         -  234 

Lake  copper,  smelting  of          -  -  286 

Lake  Superior  Copper  Region,  geology  of        -  -  220 

Lavas  -  -  148 

Lead,  detection  of,  in  copper  ores  -                                       -  90 

Levels  -  177 

Lettsomite        -  88 

Libethenite       -  -  ib. 

Lodes  -  157 

London  Mine   -  -  278 

Maillechort      -  -  359 

Malachite          -  86 

Manassas  Gap  Mine      -  -  265 

Manitou  Mining  Company         -  .  254 

Mannheim  Gold                         -  -  355 

Mary's  Mine     -                           r  r             -             -             -  278 


INDEX.  XV 

PAGE 

Masses  -  227 

Medals  -  368 

Mine  La  Motte  -  215 

Mineral  Hill  Mine          -  -  264 

Mineral  Point  -  -254 

Mineral  veins  -  -             -  150 

alluvial  deposits  -  150 

contact  deposits  -  153 

disseminated  in  eruptive  rock     -  -  152 

eruptive  masses  -  ib. 

fahlbands  -  154 

origin  of  -  166 

regular  deposits  -  156 

stockwerke         -  -  153 

stratified  beds     -  151 

Mines  and  Mining         -             -  -                           -  143 

of  Algeria           -  -  207 

Argentine  Republic    -  213 

Atlantic  States            -  -  256 

Australia        -  -             -             -  208 

Austria           _-_.--  203 

Britain            -  -  194 

Canada           -  -  254 

Carrol  County,  Virginia  -                                       -  267 

Chili  -             -             -             -  210 

Cuba  -  190 

France           -  -  202 

India  -  207 

Italy  -  203 

Jamacia         -.__-_  213 

Japan  -  207 

Lake  Superior  -            -  216 

history  of  -             -  ib. 

Mississippi  Valley      -  -             -             -  253 

New  Jersey    -  -            -             -  280 

Norway  and  Sweden  -  205 

Peru  -  209 

Prussia           -             -  -             -             -             -  202 


XVI  INDEX. 

PAGE 

Mines  of  Russia  -  204 

Spain  -  203 

Tennessee      -  -  298 

Turkey           -  203 

United  States              -             -  -  215 

ventilation  of     -  -  182 

Minnesota  Mine  -  247 

Mosaic  gold     -  -  356 

Muntz's  metal  -  -  355 

Native  Copper  Mining  Company            -  -  229 

silver  and  mercury  in   -  -             -             -  70 

New  York  and  Michigan  Mine  -  228 

Nicking  buddle  -  190 

Nitrate  of  copper          -  -  59 

Nitride  of  copper          -  -  40 

North  American  Mining  Company         -  -  242 

North  Carolina  Copper  Mining  Company  -                           -  272 

North- West  Mining  Company  of  Detroit  -  236 

Michigan  -                           -  235 

Norwich  Mining  Company        -  -  252 

Olivenite          -  88 

Ontonagon  District      -  -  244 

Ores,  crushing  of          -  -  183 

dressing  -  ib. 

jigging    -  -  186 

stamping  -  184 

washing  -  185 

of  copper  -  68 

analysis  of       -  90 

classification  of  68 

for  smelting   -  289 

Oxides  of  copper          -  34 

Oxychlorides  of  copper  -  45 

Pakfong           -------  359 


INDEX.  XV11 

PAGE 

Patapsco  Mine  -  265 

Percussion  table           -  -  190 

Perkiomen  Mine            -  -  283 
Peroxide  of  Copper  (see  Binoxide) 

Phillipsite         -  V? 

Phoenix  Mining  Company          -  -  230 

Phosphate  of  copper    -  -                           -  58 

Phosphide  of  copper     -  42 

Phosphorochalcite        -  -  88 

Pinchbeck        -  -  S55 
Pittsburg  and  Boston  Mining  Company,  (see  Cliff  Mine.) 

Isle  Royale  Mining  Company      -  244 

Platin  -  355 

Polk  County  Mine        -  -  2V  8 

Polysulphides  of  copper            -  -  42 

Portage  Lake  Mining  District  -  -  258 

Porphyry          -  -  147 

Prince's  metal  -  355 

Protoxide  of  copper     -  -  36 

hydrated  -  -  38 

salts  of     -            -  -             -             -  49 


Rack   - 
Red  brass 

copper 

oxide  of  copper,  (see  suboxide.) 
Refining 
Resin  of  copper 
Rocks  - 

classification  of 
Rosette  copper 
Royal  Santiago  Mining  Company 


191 

355 

n 


44 
144 
146 
346 
215 


Santa  Rita  del  Cobre  Mir 
Scheele's  green 
Schists 
Schuyler  Mine 


285 

66 

148 

281 


XV111  INDEX. 

PAGE 

Schweinfurth  green 

Selvages           -  -  163 

Shafts  -  1T5 

Shoding           -  -  173 

Silicate  of  suboxide  of  copper  -  49 

copper 

Silicofluoride  of  copper  -  47 

Silver,  detection  of,  in  copper  ores  -                                       -  91 

Similor  -  355 

Siskawit  Mine  -  244 

Slag     -  -  303 

Sleeping  table  -  189 

Slickensides     -  -  164 

Slope  -  -  157 

Smelting,  Birkmyre's  process   -  -  334 

Brankert's  process    -  -  333 

Davies'  process        -  -  334 

De  Sussex's  process  -  335 

English  process        -  -                                         -  288 

French  process          -  -             -             -  337 

Low's  process           -  -  336 

Mansfeld's  process    -  -  340 

Napier's  process        -  -  331 

Parkes'  process         -  -  336 

Rivot  and  Phillips'  process  -  -  333 

Trueman  and  Cameron's  process      -  -  336 

South  Cliff  Mine          -  -  242 

Speculum  metal            -  -                                         -  375 

Springfield  Mine           -  263 

Stamp  work     -  -  228 

Star  Mining  Company  -                                         -  234 

Stoping                                        -  -  177 

Strings                                         -  -  157 

Subacetate  of  copper  -  49 

Subchloride  of  copper  -                           -  43 

Subfluoride  of  copper  -  47 

Suboxide  of  copper      -  -  84 

hydrated   -----  36 


INDFX. 


PAGE 

Suboxide  of  copper,  salts  of     - 

-     %      -         48 

Subsulphide  of  copper 

40 

Subsulphophosphite  of  copper 

67 

Sulphate  of  copper 

51 

and  potassa 

58 

basic          - 

57 

Sulphite  of  suboxide  of  copper 

48 

Sulphide  of  copper       -             - 

41 

Surface  indications      - 

-       170 

Swansea,  mode  of  smelting  copper  at  - 

-       288 

sales  of  ore  at 

-     "        -       386 

Tam-ta.m  metal 

-       374 

Tennantite        -                          - 

83 

Tenorite           -                          ... 

72 

Terfluoride  of  copper  - 

47 

Threads 

-       157 

Thrombolite     -                                       - 

88 

Timbering         - 

181 

Tinning  copper 

-       376 

Toltec  Consolidated  Mine 

-       247 

Tombac                         - 

-       355 

Trachytes         ----- 

-       147 
-         ib 

Tutenag           - 

-       360 

Tyrolite            - 

89 

Underlie 

-       157 

Variegated  copper 

77 

Veins,  Weissenbach's  classification  of- 

-       156 

gash      ----- 

-       159 

opening  of 

-       172 

segregated         - 

-       158 

true       -                                       - 

-       160 

Wall     - 

-       157 

Warren  Mine    ----- 

-       257 

XX  INDEX. 

PAGE 

Washington  Mining  Company  - 
Waterbury  Mining  Company  - 
Wheal  Jamaica 

Whim-  -       ltJG 

White  metal     -  -       310 

Wild  Cat  Mine  -       269 

Winzes  -       177 

Wolfsbergite    -  -         83 

Yellow  metal  -------       354 


CHAPTER  I. 

CHEMICAL   RELATIONS   OP   COPPER. 

COPPER  being  an  abundant  metal,  easily  reduced  from 
some  of  its  ores,  and  susceptible  of  a  great  variety  of 
important  applications,  might  be  supposed  to  be  dis- 
covered at  an  early  period  of  the  world's  history. 
Accordingly  we  find  it  among  the  few  metals  mentioned 
in  the  Pentateuch.  Moses  tells  us  that  the  antedilu- 
vian metallurgist,  Tubal  Cain,  was  the  father,  that  is,  the 
instructor  or  master  of  all  those  that  work  in  brass  and 
iron.  The  Egyptians  used  it  largely,  and  with  them,  as 
with  other  ancient  nations,  it  supplied  the  place  of  steel. 
Hesiod  tells  us  that  iron  was  a  late  invention,  brass 
being  the  material  out  of  which  the  weapons  of  antiquity 
were  fabricated.  The  shields,  helmets  and  swords  of 
Homer's  heroes  were  also  formed  of  it.  In  later  times, 
when  iron  had  superseded  the  ancient  metal,  the  same 
name,  zaixtvt,  originally  applied  to  the  armorer,  and 
meaning  a  worker  in  brass  or  bronze,  was  retained  as 
the  appellation  of  the  blacksmith  who  wrought  in  iron. 
The  brass  of  the  ancients  or  2<axo$,  a  word  derived  from 
the  Arabic,  and  signifying  any  thing  capable  of  being 
polished,  was  not  the  compound  to  which  we  apply  that 
name,  but  a  sort  of  bronze  or  alloy  of  copper  and  tin. 

Our  English  word  copper,  together  with  the  terms 
3 


26  CHEMICAL  RELATIONS  OF  COPPER. 

used  in  most  of  the  modern  languages  to  designate  this 
metal,  is  derived  from  the  Latin  cuprum,  which  itself 
comes  from  Cyprus,  or  Kupros,  as  it  was  spelt  by  the 
Greeks,  an  island  sacred  to  Venus,  where  it  was  exten- 
sively mined  and  smelted  in  very  ancient  times.  The 
alchemical  title  of  copper  was  Venus,  and  the  symbol 
of  the  planet  was,  in  that  singular  old  astro-chemical 
system,  applied  to  the  metal. 

Gopper.  Copper  is  distinguished  from  all  metals, 
except  titanium,  by  its  color,  which  is  a  fine  brownish 
red,  slightly  inclining  to  yellow.  When  reduced  to  a 
very  thin  pellicle,  it  is  transparent,  and  by  transmitted 
light,  has  a  beautiful  green  color.  Films  of  this  kind 
may  be  obtained  by  heating  a  little  oxide  or  chloride  of 
copper  in  a  glass  tube  through  which  a  current  of 
hydrogen  gas  is  passed,  when  the  glass  is  coated  by  a 
layer  of  metal  of  extreme  tenuity,  displaying  a  red 
color  by  reflected,  and  a  green  by  transmitted  light. 
When  warmed  or  rubbed  it  gives  off  a  disagreeable 
smell  and  a  peculiar  faint  nauseous  metallic  taste.  It 
is  susceptible  of  a  high  but  fugacious  polish,  as  it  is 
extremely  liable  to  tarnish. 

Native  copper  is  occasionally  found  crystallized  in 
regular  octahedra.  These  may  also  be  obtained  arti- 
ficially by  allowing  fused  copper  to  cool  very  gradually 
in  a  crucible,  then  breaking  the  outer  crust  and  pouring 
out  the  still  liquid  metal,  when  the  inner  surfaces  will 
be  found  to  be  lined  with  small  crystals  of  this  form. 
The  galvanic  process  of  precipitating  copper  yields  the 
same  result.  When  thrown  down  from  its  solutions  by 
other  metals,  its  crystals  have  usually  a  cubical  form, 
and  are  very  small. 


CHEMICAL  RELATIONS  OP  COPPER.  27 

Copper  is  both  malleable  and  ductile.  Gold  and  } 
silver  only  exceed  it  in  malleability,  while  in  ductility 
it  is  surpassed  by  gold,  silver,  platinum  and  iron.  It 
can  be  beaten  into  very  thin  leaves,  while  it  cannot  be 
drawn  out  to  extremely  fine  wire.  In  a  state  of  minute 
division,  it  welds  like  gold,  a  property  which  has  been 
taken  advantage  of  in  the  manufacture  of  medals.  Fine 
copper  powder  is  strongly  forced  into  the  die,  and  an 
unusually  sharp  and  clear  impression  is  thus  obtained. 
The  medal  may  be  afterwards  hardened  by  careful 
annealing. 

It  is  more  tenacious  than  any  of  the  other  metals 
excepting  iron.  A  copper  wire,  one-tenth  of  an  inch 
in  diameter,  is  capable  of  supporting  a  Aveight  of  385  y; 
pounds.  It  is  soft  enough  to  be  cut  with  a  knife,  but  is 
more  resisting  than  lead.  It  is  the  most  sonorous  of 
the  metals,  and  constitutes  an  important  part  of  those 
alloys  which  are  used  in  the  manufacture  of  bells, 
gongs,  &c. 

The  specific  gravity  of  copper  fused  in  the  open  air  \ 
is  lower  than  that  of  the  metal  under  other  circum- 
stances, because  some  oxygen  is  absorbed  from  the  air. 
It  reaches  only  8.7  or  8.8.  Fused  under  a  protecting 
slag,  its  specific  gravity  is  8.91  to  8.921.  That  of  the 
unignited  wire  is  8.939  to  8.949;  of  the  ignited  wire, 
8.93 ;  of  flattened  wire  and  well  rolled  sheet,  8.95  to 
8.96. 

Copper  melts  at  a  full  red  heat.  The  fusion  point  has 
been  stated  to  be  1996°  F. ;  intermediate  between  those 
of  silver  and  gold.  At  a  white  heat  it  burns  with  a  bril- 
liant green  flame.  At  high  temperatures  below  its 


28  CHEMICAL  RELATIONS  OE  COPPER. 

point  of  combustion  it  is  volatile,  and  even  at  its  fusing 
point  a  small  quantity  escapes  into  the  atmosphere.  In 
the  most  carefully  managed  furnaces,  this  loss  is  unavoid- 
able, and  has  been  said  to  amount  to  the  fourth  of  one 
per  cent.,  though  bad  management  will  raise  it  very 
much  above  this.  It  is,  however,  difficult,  if  not  impos- 
sible, to  determine  with  any  accuracy  the  amount  of  loss 
from  this  source,  because  it  cannot  be  ascertained  with 
precision  how  much  soaks  into  furnace  bottoms  and  how 
much  is  lost  in  other  furnaces  in  the  reduction  of 
refinery  slag.  All  the  ores  of  copper  are  more  or  less 
volatile,  and  in  a  furnace  without  a  culvert  much  metal 
must  necessarily  be  lost.  The  author  has  known  20 
tons  of  fine,  impalpable,  reddish  brown  powder,  con- 
taining on  an  average  14  per  cent,  of  copper,  to  be 
taken  out  of  the  culvert  of  a  smelting  establishment,  as 
the  residuum  of  about  3000  tons  of  ore,  averaging  22 
per  cent.  This,  however,  must  not  be  taken  by  any 
means  as  the  standard  of  volatility  for  ores  of  copper, 
because  much  of  this  was,  in  all  probability,  swept  up 
the  chimney  mechanically  by  the  strong  draught  of  air. 
Commercial  copper  varies  remarkably  in  purity. 
Russian  copper  is  generally  very  nearly  chemically 
pure.  Some  of  the  American  copper  is  also  very  free 
from  impurities.  Most  of  the  refined  metal,  however, 
in  all  countries,  contains  lead,  iron  and  antimony,  and 
the  best  of  it  is  scarcely  ever  free  from  traces  of  carbon 
and  suboxide  of  copper.  The  pig  copper  of  commerce 
is  of  course  always  impure.  That  from  South  America 
is  often  extremely  bad,  being  not  only  carelessly 
smelted  and  therefore  containing  the  ingredients  of  the 


CHEMICAL  RELATIONS  OF  COPPER.  29 

ore,  but  fraudulently  mixed  -with  fragments  of  old  iron 
to  increase  the  weight.  Pigs  of  this  metal,  -which  are 
nothing  but  bars  of  iron  encased  in  copper,  are  occa- 
sionally imported  into  this  country  from  the  smelting 
houses  on  the  west  coast  of  South  America. 

For  many  laboratory  uses,  good  commercial  copper  is  — 
sufficiently  pure.  The  turnings  are  often  used,  and 
then  it  is  necessary  that  they  should  undergo  some 
little  preparation.  The  grease  with  which  they  are 
commonly  contaminated  is  burned  off  by  heating  them 
to  redness  in  the  open  air.  This  cannot,  however,  be 
done  without  coating  them  with  black  oxide,  which  is  to 
be  removed  by  heating  them  in  a  current  of  dry  hydro- 
gen gas,  until  no  more  steam  is  given  off,  and  the  sur- 
face is  perfectly  pure  and  free  from  tarnish  of  any  kind. 
The  metal  is  then  allowed  to  cool  in  an  atmosphere  of  •• 
hydrogen.  * 

Strips  of  sheet  copper  are  often  used  in  some  ana- 
lytical processes,  such  as,  for  example,  Levol's  method 
of  ascertaining  the  quantity  of  copper  in  an  ammoniacal 
solution  of  the  black  oxide,  or  Eeinsch's  test  for  arsenic. 
For  the  former  purpose,  common  sheet  copper  will 
answer,  provided  its  surface  has  been  carefully  cleansed. 
For  the  latter,  the  author  has  been  in  the  habit  of  using 
the  faces  of  Swiss  watches.  The  enamel  is  carefully 
beaten  off,  and  the  copper  passed  through  a  gold- 
beater's mill.  The  surface  being  then  cleansed  with 
dilute  acid  is  extremely  sensitive  to  the  smallest  traces 
of  the  poison  in  question.  Copper  gauze  is  often  used 
for  the  same  purpose. 

Perfectly  pure  copper  is  obtained  by  precipitating  the  - — 
3* 


30  CHEMICAL  RELATIONS  OF  COPPER. 

metal  from  a  solution  of  chemically  pure  sulphate  of 
copper,  on  a  surface  of  copper,  by  the  galvanic  pro- 
cess. It  is  also  procured  by  passing  a  stream  of  hydro- 
gen through  a  heated  tube  containing  absolutely  pure 
oxide  of  copper.  It  is  then  in  the  form  of  a  red  powder 
•which,  however,  readily  assumes  the  metallic  lustre  on 
being  rubbed  between  two  hard  polished  surfaces. 

At  ordinary  temperatures,  copper  does  not  tarnish 
•when  exposed  to  perfectly  dry  air  or  oxygen  gas.  In 
moist  air,  especially  if  acid  vapors  be  present,  it  be- 
comes rapidly  coated  with  a  layer  of  oxide,  which 
absorbs  carbonic  acid  from  the  atmosphere  and  is  con- 
verted into  a  green  basic  carbonate,  mingled  with  oxide, 
commonly  known  as  verdigris.  Every  imaginable  tint 
of  olive  green  is  produced  by  the  variable  mixtures  of 
these  two  ingredients.  A  surface  of  metallic  copper, 
moistened  with  acid  and  exposed  to  the  atmosphere, 
combines  with  the  oxygen  of  the  air,  and  the  resulting 
oxide  unites  with  the  acid,  producing  a  neutral  salt, 
which,  by  the  action  of  its  oxygen  upon  the  metal,  is 
ultimately  reduced  to  basic  salt  adhering  firmly  to  the 
metal. 

In  a  solution  of  ammonia,  copper  is  also  oxidated,  a 
blue  solution  resulting.  Dilute  solutions  of  chloride 
of  sodium  (common  salt)  dissolve  copper  very  rapidly, 
while  concentrated  solutions  of  the  same  salt  exert  little 
or  no  effect  on  it.  It  has  been  suggested  that  this 
action  is  a  galvanic  one,  circles  being  formed  between 
the  copper  and  the  small  particles  of  foreign  metals  and 
other  impurities  existing  in  it,  though  it  is  not  easy  to 
see  how  the  dilution  renders  the  solution  more  active. 


CHEMICAL  RELATIONS  OF  COPPER.  31 

At  a  white  heat  copper  feebly  decomposes  steam, 
converting  it  into  oxygen  and  hydrogen.  At  common 
temperatures  this  change  does  not  take  place.  Acids 
even  do  not  enable  it  to  effect  the  decomposition  of 
water  at  the  ordinary  temperature.  In  a  state  of  fine 
division,  copper  is  dissolved  by  hydrochloric  acid,  while 
in  larger  masses  this  reagent  scarcely  affects  it.  Its 
action  is  probably  dependent  upon  the  oxygen  of  the 
atmosphere.  Strong  sulphuric  acid,  especially  when 
aided  by  heat,  dissolves  it,  with  the  evolution  of  sul- 
phurous acid  gas,  a  phenomenon  which  shows  that  the 
oxidation  of  the  metal  takes  place  at  the  expense  of  the 
acid  itself,  and  not  of  the  water  with  which  it  is  com- 
bined. Cold  nitric  acid,  of  any  degree  of  concentra- 
tion, dissolves  it  rapidly,  with  the  evolution  of  copious 
red  fumes  of  hyponitric  acid,  resulting  from  the  action 
of  atmospheric  air  upon  the  deutoxide  of  nitrogen. 

Fatty  matters  also  predispose  copper  strongly  to 
unite  with  oxygen.  Hence  vessels  of  copper  can  only 
be  used  with  safety  for  a  very  few  culinary  purposes,  as 
its  compounds  are  decidedly  poisonous. 

The  symbol  of  copper  is  Cu.  Its  equivalent,  as  de- 
termined by  the  reduction  of  the  black  oxide  by  hydro- 
gen, is  31.71  on  the  hydrogen,  and  396.7  on  the  oxygen 
scale. 

USES  OF  COPPER.  Copper  is  used  for  a  great  variety 
of  purposes  in  the  arts.  One  of  the  most  extensive  of 
its  applications  is  that  of  sheathing,  and  bolts  for  ships. 
It  is  of  service  here,  because  it  is  less  readily  acted  upon 
by  sea-water  than  any  other  of  the  cheap  metals,  and 
because  the  friction  of  the  water  upon  it  is  less  than  it 


32  CHEMICAL  RELATIONS  OP  COPPER. 

would  be  upon  wood.  Iron  cannot  be  substituted  for  it 
even  in  a  ship's  bolts,  because  the  sea  air  is  sufficiently 
impregnated  with  salt  to  corrode  this  metal  with  great 
rapidity. 

It  is  used  also  to  alloy  the  precious  metals.  These  are 
too  soft  to  be  worked  to  any  advantage  without  the 
introduction  of  copper,  which  gives  the  necessary  hard- 
ness, without  diminishing  the  lustre,  and  if  proper  pre- 
cautions be  taken,  without  impairing  the  color  of  the 
alloys.  It  is  consequently  the  common  alloy  in  jewelry 
and  in  gold  and  silver  coinage.  Its  combinations  with 
the  cheaper  metals,  which  are  very  important,  will  be 
described  in  another  place. 

It  is  also  peculiarly  adapted  to  boilers  in  which  saline 
waters  are  to  be  used,  as  the  incrustations  are  not  so 
adherent  as  they  are  to  iron  boilers,  neither  are  they  so 
corrosive  in  their  action.  They  are  easily  removed,  and 
leave  the  surface  of  the  boiler  perfectly  clean  and  bright, 
so  that  the  thickness  of  the  boiler  not  being  diminished, 
there  is  none  of  that  danger  of  explosion  which  attends 
the  use  of  iron  boilers  under  similar  circumstances. 

As  copper  was  one  of  the  earliest,  so  it  continues  to 
be  the  best  material  on  which  to  execute  artistic  engra- 
vings. Steel  has  been  lately  substituted,  from  motives 
of  economy,  as  it  is  capable  of  yielding  a  larger  number 
of  impressions,  but  it  is  not  susceptible  of  that  mellow- 
ness and  richness  of  effect  to  be  obtained  from  copper. 
Etchings  are  made  upon  the  surface  by  covering  it  with 
a  varnish,  and  then  engraving  through  this  with  a  sharp 
tool.  The  shadows  are  produced  by  cutting  into  the 
plate  with  gravers  and  deepening  the  impressions  with 


CHEMICAL  RELATIONS  OF  COPPER.  33 

acid,  while  varnish  is  spread  over  the  lights  and  middle 
tints  to  protect  them  from  the  corrosive  action.  The 
rationale  of  this  is  that,  when  these  plates  are  put  upon 
the  press,  the  darkest  portions  of  the  impression  corres- 
pond with  the  broadest  and  deepest  furrows  upon  the 
surface  of  the  copper. 

NON-SALINE   COMPOUNDS   OP   COPPER. 

Oxides  of  Copper.  When  copper  is  heated  in  the 
air,  it  is  covered  with  a  red  film  of  suboxide  which 
passes  gradually  into  the  black  or  protoxide.  When 
copper  is  fused  in  the  atmosphere,  tarnishes,  of  various 
hues  of  yellow,  red,  purple  and  black,  form  on  the  surface. 
These  indicate  various  admixtures  of  the  two  oxides  with 
metal,  and  may  be  conveniently  seen  on  the  surface  of 
ingots  sent  to  market.  When  these  have  been  allowed 
to  cool  too  long  in  the  air  after  being  cast,  they  are 
invariably  coated  with  a  black  layer.  When  they  have 
been  early  immersed  in  the  water,  the  tarnish  is  either 
an  orange  yellow,  a  fine  ruby  red,  or  a  mixture  of  the 
two.  It  is  upon  the  proper  management  of  this  that 
the  preparation  of  Japan  copper  depends.  This  is  cast 
in  small  moulds,  and  the  moment  it  becomes  consoli- 
dated, it  is  thrown  into  water  where  it  becomes  covered 
with  the  well  known  beautiful  red  film  of  suboxide. 
Heated  in  oxygen  or  the  flame  of  the  compound  blow- 
pipe, copper  burns  with  a  rich  green  flame,  and  is  wholly 
converted  into  black  oxide.  Its  tarnish,  gradually  ac- 
quired from  the  atmosphere,  is  at  first,  a  warm,  deep 
brown,  which  gradually  passes  into  the  dark  olive-green, 


34  CHEMICAL  RELATIONS  OF  COPPER. 

so  highly  prized  by  antiquaries,  a  color  produced  by  the 
mixture  of  the  carbonate  with  the  two  oxides. 

Copper  forms  four  definite  compounds  with  oxygen. 

1.  The  suboxide,  or  red  oxide,  Cu20. 

2.  The  protoxide  or  black  oxide,  CuO. 

3.  The  binoxide,  Cu02. 

4.  Cupric  acid  the  composition  of  which  is  undeter- 
mined. 

Suboxide  of  Copper*  Cu20,  71.42.  The  native 
dioxide  will  be  described  in  the  next  chapter.  It  is 
often  found  as  a  product  of  furnace  operations.  Much 
of  the  slag  from  a  refining  furnace  is  composed  of  this 
oxide.  It  then  is  of  a  deep  red  color,  oftener  porous 
than  compact,  and  mingled  with  various  impurities. 

It  may  be  obtained  by  several  processes. 

1.  Ignite  in  a  well  covered  crucible  a  mixture  of 
31.71  parts  of  metallic  copper  with  39.71  parts  of  black 
oxide.     This  mixture  aggregates  at  a  high  temperature 
and  a  red  fused  mass  of  the  suboxide  is  obtained.     An 
analogous  process  of  reducing  the  black  oxide  is  to  heat 
to  redness  in  a  carefully  closed  crucible,  alternate  layers 
of  fine  copper  sheet  and  black  oxide. 

2.  Heat  in  a  crucible  a  mixture  of  subchloride  of 
copper  with  carbonate  of  soda,  and  then  dissolve  out 
the  chloride  of  sodium  and  the  excess  of  carbonate  of 
soda  by  water.     The  suboxide  is  left  as  a  deep  red  crys- 
talline powder.     A  very  fine  metallic  pigment  has  been 

*  It  is  proper  to  state  here  that  this  suboxide  is  called  by  some  the 
protoxide,  while  the  black  oxide  is  rated  as  a  peroxide.  The  form  also 
adopted  in  the  text,  however,  is  that  which  is  now  universally  adopted 
by  chemists. 


CHEMICAL  RELATIONS  OF  COPPER.  35 

made  by  a  process  resembling  this.  Sulphate  of  copper 
is  mixed  -with  carbonate  of  soda,  in  the  proportion  of 
100  parts  of  the  former  to  59  of  the  latter.  These 
mixed  salts  are  fused  in  their  water  of  crystallization  at 
a  low  temperature,  and  the  heat  is  continued  till  the 
mixture  is  dry,  when  25  parts  of  finely  divided  metallic 
copper  are  mixed  with  and  the  whole  is  heated  to  white- 
ness, in  a  covered  crucible,  for  twenty  minutes. 

3.  A  solution  of  some  salt  of  the  black  oxide  is 
mixed  with  a  solution  of  grape  sugar,  (cane  sugar  may 
be  converted  into  this  variety  by  boiling  it  with  a  few 
drops  of  dilute  sulphuric  acid.)  Potassa  is  then  added 
till  the  precipitate  first  formed  is  completely  re-dissolved, 
forming  a  violet-blue  fluid.  This  is  boiled  for  some 
time,  when  the  suboxide  is  deposited  in  small  bright  red 
crystals. 

This  oxide  is  always  formed  when  a  large  quantity  of 
metallic  copper  is  fused  under  scoriae  sufficiently  thin  to 
admit  a  little  atmospheric  air.  It  is  often  found  on  the 
sides  of  refining  furnaces  mixed  with  the  black  oxide, 
and  then  the  mass  is  crystalline  in  its  texture,  dark 
gray  in  color,  with  metallic  lustre,  and  flecked  with  splen- 
did ruby-red,  semi-transparent  particles. 

This  compound  varies  in  color  from  a  brownish  cop- 
per-red to  a  pure  carmine  tint.  In  a  dry  atmosphere  it 
may  be  kept  a  long  time,  but  moisture  rapidly  peroxi- 
dates  it.  Heated  to  redness,  it  is  converted  into  the 
black  oxide.  The  acids  act  upon  it  variously.  Most  of 
them  decompose  it  into  a  salt  of  the  black  oxide  and 
metallic  copper.  Strong  nitric  acid  oxidates  it  with 
the  evolution  of  binoxide  of  nitrogen.  Hydrochloric 


36  CHEMICAL  RELATIONS  OF  COPPEK. 

acid  dissolves  it,  forming  a  colorless  solution,  from  which 
the  alkalies  and  their  carbonates  throw  down  yellow 
and  red  precipitates,  and  ferrocyanide  and  iodide  of  po- 
tassium white  or  brownish  ones.  Ammonia,  dissolves  it 
to  a  colorless  fluid,  which  rapidly  becomes  blue  when  ex- 
posed to  the  air,  in  consequence  of  absorption  of  oxygen. 
This  blue  solution  is  decolorized  again  by  being  allowed 
to  remain  in  a  well-closed  bottle  in  contact  with  strips 
of  metallic  copper. 

Fused  with  glass,  this  oxide  forms  a  fine  rich  ruby- 
red,  when  proper  care  is  taken  to  prevent  oxidation.  A 
little  metallic  tin  is  often  mixed  with  it  for  this  purpose. 
Its  coloring  power  is  very  intense,  so  that  an  exceed- 
ingly thin  film  may  be  blown  out  as  a  covering  to  a 
vessel  of  transparent  glass.  The  outer  film  may  be 
then  cut  through,  and  various  forms  obtained  in  color- 
less glass.  Pastes  are  also  colored  by  it  to  imitate  the 
ruby  and  the  garnet. 

Hydrated  suboxide  of  copper,  4Cu20,HO.  This  is 
prepared  by  decomposing  the  subchloride  with  potassa 
or  soda.  It  is  a  yellow  powder,  which  rapidly  absorbs 
oxygen  from  the  air,  and  must,  therefore,  be  dried  in 
vacuo. 

The  suboxide  is  a  feeble  base,  forming  salts,  which 
will  be  presently  described. 

Oxide  or  Protoxide  of  Copper,  Black  Oxide.  CuO. 
39.71.  This  oxide  is  found  native,  and  is  always 
formed  when  copper  is  heated  in  the  air,  or  precipi- 
tated from  its  solutions  by  alkalies.  The  author  has, 
in  his  collection,  specimens  of  this  oxide  in  acicular 
crystals,  lining  the  cavities  of  fire-brick  from  the  sides 


CHEMICAL  RELATIONS  OF  COPPER.  37 

of  a  refining  furnace,  through  which  it  had  passed  either 
by  filtration  or  sublimation,  probably  the  latter. 

It  is  prepared  by  roasting  copper  filings,  or  calcining 
the  finely  divided  copper  obtained  from  the  ignition  of 
the  acetate,  but  better  by  igniting  the  nitrate.  Several 
methods  of  performing  this  ignition  have  been  suggest- 
ed. The  most  common  is  to  heat  the  nitrate  to  white- 
ness in  a  Hessian  crucible.  An  improvement  on  this 
process  has  been  made  by  heating  the  salt  in  a  vessel 
made  by  striking  up  an  entire  piece  of  sheet-copper. 
This  vessel  is,  indeed,  corroded  by  the  process,  but  it 
furnishes  additional  portions  of  oxide.  Another  method 
is  to  mix  the  nitrate  with  half  its  weight  of  copper 
filings,  to  expose  the  mixture  to  the  air,  and  to  ignite 
the  basic  nitrate  thus  obtained.  The  object  of  the  last 
named  modifications  is  to  increase  the  yield,  and  so  to 
economize  the  acid.  Another  method  is  to  ignite  the 
hydrated  oxide  obtained  by  precipitating  copper  salts 
with  potassa. 

Oxide  of  copper,  as  ordinarily  seen,  is  a  powder  ran- 
.ging  in  tint  from  a  deep  brown  to  a  blueish  black. 
When  strongly  heated,  it  fuses,  and,  at  a  very  high 
temperature,  loses  some  of  its  oxygen,  being  converted 
into  mixture  of  the  black  and  red  oxides.  The  fused 
oxide  is  a  deep,  lustrous,  iron-gray  mass.  Fused  with 
hydrate  of  potash  or  soda,  it  forms  a  blue  or  green 
mass,  easily  decomposed  by  water.  When  this  fused 
mass  is  allowed  to  cool  slowly,  the  oxide  crystallizes  in 
tetrahedra,  which  are  easily  obtained  by  dissolving  out 
the  alkalies  with  water. 

Deoxidating  agents,  such  as  protoxide  of  iron,  proto- 
4 


38  CHEMICAL  RELATIONS  OF  COPPER. 

chloride  of  tin,  and  organic  matters  at  a  boiling  tempe- 
rature, convert  it  into  dioxide.  Hydrogen  and  carbon, 
aided  by  heat,  easily  reduce  it  to  metallic  copper.  The 
former  of  these  agents  effects  the  deoxidation  at  a  heat 
below  redness. 

This  oxide  is  insoluble  in  water,  but  dissolves  in  acids, 
forming  important  salts.  All  the  valuable  salts  of  cop- 
per have  this  oxide  for  their  base. 

The  oxide  of  copper  is  extensively  employed  in  or- 
ganic analysis  as  a  source  of  oxygen  ;  the  substance  to 
be  analyzed  is  mixed  with  the  perfectly  dry  and  warm 
oxide,  introduced  into  combustion-tube,  and  gradually 
heated  to  redness.  The  hydrogen  and  carbon  are  con- 
verted into  water  and  carbonic  acid,  which  are  collected 
in  a  proper  apparatus. 

This  oxide  is  used  to  color  glass,  green  or  blue.  It  is 
employed  in  the  manufacture  of  artificial  gems  to  imi- 
tate the  emerald,  for  which  purpose  it  is  usually  mixed 
with  chrome  or  sesquioxide  of  iron. 

Hydrated  Oxide  of  Copper.  CuO,2HO.  This  is 
obtained  as  a  pale  blue  precipitate  by  adding  excess  of 
a  solution  of  potassa  to  a  solution  of  any  copper  salt. 
Should  too  little  alkali  be  used,  a  basic  salt  will  be 
formed.  The  water  is  very  feebly  united  with  this  oxide, 
for  should  the  blue  precipitate  be  boiled  with  its  super- 
natant solution,  it  is  converted  into  the  heavy,  anhy- 
drous black  oxide.  The  same  change  takes  place,  but 
more  slowly,  when  this  hydrated  oxide  is  exposed  to  the 
air.  In  order,  therefore,  to  procure  the  hydrated  oxide 
of  the  formula  given  above,  it  must  be  dried  under  the 
exhausted  receiver  of  nn  air-pump. 


CHEMICAL  HELATIOKS  OF  COPPER.  39 

The  pigment  known  as  blue  verditer,  has  this  ox- 
ide for  its  basis.  It  dissolves  readily  in  acids,  and  in 
•water  of  ammonia.  With  the  latter  liquid  it  forms  a 
fine  purplish  blue  solution,  called  celestial  water.  Two 
definite  compounds  with  ammonia  with  oxide  of  copper 
and  water  have  been  obtained.  Their  formulae  are 
CuO,NH3,4HO,  and  3CuO,2NH3,6HO. 

The  hydrated  oxide  dissolves  to  a  slight  extent  in  cold 
concentrated  solutions  of  potassa  and  soda,  forming  blue 
liquids,  which  deposit  the  black  oxide  when  heated. 

It  is  by  the  reactions  of  this  oxide  that  copper  is  usu- 
ally detected  and  estimated.  For  a  description  of  these 
reactions,  the  reader  is  referred  to  Chapter  III. 

Binoxide  or  Peroxide  of  Copper,  Cu02.  When 
the  hydrated  protoxide  of  copper  is  treated  with  perox- 
ide of  hydrogen,  the  blue  substance  assumes  a  brownish 
yellow  color,  and,  by  the  abstraction  of  another  atom  of 
oxygen  from  the  fluid,  is  converted  into  a  deutoxide. 
A  very  slight  elevation  of  temperature  decomposes  it 
into  protoxide  and  oxygen :  acids  have  the  same  effect. 
Under  water  it  undergoes  spontaneous  decomposition, 
and  can  only  be  dried  over  sulphuric  acid  in  vacua. 
It  is  of  no  special  interest. 

Cuprio  Acid.  When  finely  divided  copper  is  fused 
Avith  hydrate  of  potassa  and  nitre,  or  when  hydrate  of 
copper  is  dissolved  in  hypochlorite  of  potassa,  a  salt  is 
obtained  in  which  a  combination  of  copper  with  oxygen 
seems  to  play  the  part  of  an  acid.  The  solution  is  blue, 
and  is  very  easily  decomposed.  Heat  precipitates 
from  it  black  oxide  of  copper,  oxygen  being  at  the  same 
time  evolved.  By  reason  of  this  instability,  this  acid 


40  CHEMICAL  RELATIONS  OF  COPPER. 

has  never  been  exhibited  in  a  separate  state,  and  there- 
fore no  atomic  constitution  can  be  assigned  to  it. 

Copper  and  Hydrogen.  Cu2H.  Wurtz  has  obtained 
a  compound  of  copper  and  hydrogen,  by  heating,  at  a 
temperature  of  158°,  a  solution  of  sulphate  of  copper 
with  hypophosphorus  acid. 

Thus  prepared,  the  hydride  of  copper  is  a  bright 
brown  po\vder,  which  oxidizes  in  the  air.  At  about 
140°  F.  it  decomposes,  being  resolved  into  metallic  cop- 
per and  hydrogen  gas.  Hydrochloric  acid  decomposes 
it,  forming  protochloride  of  copper  which  dissolves, 
while  hydrogen  gas  is  liberated. 

Copper  and  Nitrogen.  By  passing  a  current  of  dry 
ammoniacal  gas  over  oxide  of  copper  (CuO)  heated 
to  599°,  a  nitride  of  copper  has  been  obtained  by  Schrb'tte, 
who  assigns  to  it  the  formula  CucN.  It  is,  however, 
mixed  with  excess  of  oxide  of  copper,  which  is  dissolved 
out  by  ammonia. 

It  is  a  deep  green  amorphous  powder,  which  is  de- 
composed with  some  violence  at  a  heat  below  redness. 
It  dissolves  in  hydrochloric  acid,  yielding  chloride  of 
copper  and  sal-ammoniac. 

COPPER  AND  SULPHUR. 

There  are  a  number  of  combinations  of  copper  and 
sulphur ;  but  those  best  understood  are  the  subsulphide, 
corresponding  with  the  dioxide  and  the  sulphide,  an- 
swering to  the  protoxide. 

Subsulphide  of  Copper.  Cu2S.  In  the  vapor  of 
sulphur  copper  burns  brilliantly,  and  this  sulphide  is 
the  result  of  the  combustion.  It  is  sometimes  found  in 


CHEMICAL  RELATIONS  OF  COPPEll.  41 

copper  furnaces,  crystallized  in  regular  octahedra.  In 
the  laboratory,  it  is  prepared  by  mixing  three  parts  of  sul- 
phur and  eight  of  copper  turnings,  heating  them  till  com- 
bination takes  place  with  evolution  of  heat  and  light, 
grinding  the  substance  thus  obtained  to  powder,  and 
heating  again  with  a  little  sulphur,  in  order  to  mine- 
ralize the  remaining  metal. 

This  sulphide  is  much  more  fusible  than  metallic  cop- 
and  is  not  decomposed  by  heat.  When  roasted  in  the 
air,  it  is  converted  partly  into  sulphate  and  partly  into 
oxide  of  copper.  It  cannot  be  reduced  by  hydrogen, 
and  when  heated  with  carbon,  it  is  only  partially  re- 
duced to  metallic  copper.  Fused  with  caustic  alkalies 
and  cyanide  of  potassium,  metallic  copper  is  separated. 
When  a  mixture  of  the  sulphate  and  subsulyhide  of  copper 
is  heated  together,  decomposition  takes  place,  metallic 
copper  and  sulphurous  acids  being  the  results.  Hydro- 
chloric acid  does  not  attack  it,  but  aqua  regia  dissolves  it. 

Sulphide  of  Copper.  CuS.  When  hydrosulphuric 
acid  or  a  soluble  sulphide  is  introduced  into  a  solution 
of  a  copper-salt,  a  black  precipitate  of  sulphide  of  copper 
falls.  This  must  be  washed  with  sulphureted  hydrogen 
water,  and  dried  rapidly  over  sulphuric  acid  in  vacuo. 

It  is  a  black  powder,  which,  when  exposed  to  the  air, 
especially  if  damp,  becomes  dusky  green  from  absorp- 
tion of  oxygen  and  conversion  into  sulphate  of  copper. 
Heated  out  of  contact  with  atmospheric  air,  it  loses  one 
half  its  sulphur,  and  is  converted  into  the  subsulphide. 
Roasted  in  the  air,  it  gives  off  sulphur  and  sulphurous 
acids,  and  is  changed  into  a  mixture  of  the  oxide  and 
sulphate  of  copper. 


42  CHEMICAL  RELATIONS  OP  COPPER. 

Boiling  sulphuric  acid  does  not  attack  it ;  hydrochlo- 
ric acid  has  hardly  any  action  upon  it,  but  nitric  acid 
dissolves  it,  separating  the  sulphur  and  forming  nitrate 
of  copper  which  remains  in  solution.  It  is  slightly  solu- 
ble in  yellow  sulphide  of  ammonium,*  but  not  in  sulphide 
of  potassium. 

HIGHER  SULPHIDES  OF  COPPER  are  said  to  have  been 
obtained  by  the  action  of  the  polysulphides  of  the  alka- 
line metals  upon  copper  salts.f 

An  oxy sulphide,  of  the  formula  5CuS,CuO,HO,  is 
said,  by  Pelouze,  to  be  precipitated  when  a  boiling 
solution  of  nitrate  of  copper,  mixed  with  excess  of 
ammonia,  is  treated  with  a  soluble  sulphide. 

COPPER  AND  PHOSPHORUS. 

When  finely  divided  copper  is  heated  in  the  vapor  of 
phosphorus,  there  is  obtained  a  gray,  brittle  metallic 
mass,  containing  about  20  per  cent,  of  phosphorus. 

A  phosphide  of  the  formula  Cu2P  is  formed  by  pass- 
ing a  current  of  hydrogen  over  heated  phosphate  of 
copper.  Another  phosphide,  Cu3P,  falls  as  a  black 
precipitate  when  phosphureted  hydrogen  is  passed 
through  a  copper  solution  of  a  copper-salt.  There  are 
other  phosphides,  but  they  have  not  been  studied. 

*  When  sulphide  of  ammonium  is  first  prepared,  it  is  colorless,  but 
after  a  time  it  becomes  yellow,  in  consequence  of  the  separation  of  sul- 
phur which  dissolves  in  the  liquid.  Its  properties  are  now  somewhat 
changed  ;  hence  the  particularizing  of  this  form  of  the  sulphide. 

•{•  The  alkaline  metals  are  sodium  and  potassium,  and  the  term 
"  polysulphides"  is  used  to  denote  those  sulphurets  of  these  metals 
which  contain  several  atoms  of  sulphur  to  one  of  metal. 


CHEMICAL  RELATIONS  OF  COPPER.  43 

SALTS  OF  COPPER. — HALOID  SALTS.* 

Sulchloride  of  Copper.  Cu2Cl.  There  are  several 
methods  of  preparing  this  compound. 

1.  A  solution  of  chloride  of  copper  is  boiled  over  me- 
tallic copper  until  its  green  color  changes  to  brown. 
The  clear  liquid  is  then  decanted  and  mixed  with  a 
large  quantity  of  water,  which  precipitates  the  subchlo- 
ride.     This   precipitate   must  be  rapidly  washed  with 
boiled  water,  and  kept  under   a  layer  of  water  in  a 
well-closed  bottle.     When   a  strip  of  copper  is  used, 
instead  of  copper  turnings  the  subchloride  is  deposited 
in  white  tetrahedral  crystals  upon  the  surface  of  the 
metal. 

2.  A  solution  of  chloride  of  copper  is  precipitated 
with  a  concentrated  solution  of  protochloride  of  tin, 

*  The  old  definition  of  a  salt  was  a  combination  of  an  acid  with  a 
base.  Subsequent  investigation,  however,  proved  that,  in  the  direct 
formation  of  many  salts,  there  was  a  decomposition  of  both  base  and 
oxide.  Thus,  when  hydrochloric  acid  is  poured  upon  soda,  this  dou- 
ble decomposition  is  effected  by  the  oxygen  leaving  the  soda  and  the 
hydrogen  abandoning  the  acid.  These  two  elements  thus  combine 
to  form  water,  while  the  chlorine  and  the  sodium  unite  to  form  a 
chloride  of  sodium,  and  not,  as  it  was  formerly  called,  a  mur- 
iate of  soda.  As  there  is  a  large  number  of  these  salts,  which 
correspond  with  chloride  of  sodium  or  common  salt  in  their 
constitution,  the  name  Haloid  salts,  (from  the  Greek  word  dx, 
signifying  common  salt,)  has  been  applied  to  the  entire  class.  Their 
characteristic  is  that  they  are  formed  by  a  direct  union  of  two  simple 
bodies,  or  of  compound  radicals  with  one  another,  or  with  a  simple 
body — commonly  a  metal. 

The  oxysalts  are  still  regarded  by  most  chemists  as  constituted  ac- 
cording to  the  old  formula,  though  some  have  classified  them  under 
the  same  head  with  the  haloids,  altering  the  acid  formula. 


44  CHEMICAL  RELATIONS  OF  COPPER. 

containing  a  little   free   acid.     The  subchloride   goes 
down.     The  reactions  are  shown  by  the  formula, 

2CuCl+SnCl==Cu2Cl+SnCl2. 

This  chloride  may  be  obtained  in  small  tetrahedral 
crystals  by  dissolving  the  amorphous  compound  in  hot 
hydrochloric  acid,  which  deposits  the  crystals  as  it  cools. 

3.  When   the  protochloride  is  heated,  it  parts  with 
half  its  chlorine,  and  is  converted  into  anhydrous  sub- 
chloride. 

4.  When  chloride  of  mercury  is  distilled  with  copper 
filings,  the  mercury  passes  over,  and  this  chloride  is  left 
behind.     Boyle,  who  procured  it  in  this  way,  called  it 
resin  of  copper,  from  its  resemblance  to  common  resin. 

This  chloride  varies  in  its  tint  according  to  its  mode 
of  preparation.  As  usually  obtained,  it  is  white,  but 
may  also  be  yellow  or  dark  brown.  It  is  fusible  at  a 
heat  just  below  redness,  (752°  F.)  and  volatile  at  a 
higher  temperature.  It  soon  changes  in  the  air,  in  con- 
sequence of  the  absorption  of  oxygen,  and  becomes 
converted  into  a  green  mixture  of  hydrated  oxide  and 
chloride.  It  is  nearly  insoluble  in  water,  but  dissolves 
in  hydrochloric  acid,  forming  a  brown  liquid,  from 
which,  as  already  stated,  water  precipitates  the  sub- 
chloride.  It  is  also  very  soluble  in  ammonia,  forming 
with  it  a  colorless  solution.  This  property  renders  it 
a  valuable  agent  in  eudiometric  analyses,  for  separating 
oxygen  from  mixed  gases.  A  solution  of  common  salt 
also  dissolves  it.  Alkalies  decompose  it,  precipitating 
from  it  the  suboxide. 

Chloride  or  Protochloride  of  Copper.  CuCl.  When 
finely  divided  copper  is  heated  in  an  atmosphere  of 


CHEMICAL  RELATIONS  OP  COPPER.  45 

chlorine  gas,  it  takes  fire,  and  forms  the  anhydrous 
chloride  of  copper.  This  is  a  yellowish  brown  sub- 
stance, which  is  decomposed  by  heat  into  chloride  and 
the  subchloride. 

The  hydrated  chloride  is  prepared  by  dissolving  the 
oxide  in  hydrochloric  acid,  or  the  metal  in  aqua  regia, 
evaporating  and  allowing  the  solution  to  crystallize. 
It  forms  beautiful  green  needles,  which  are  very  deli- 
quescent and  easily  soluble,  both  in  water  and  alcohol. 
When  the  latter  solution  is  kindled,  it  burns  with  a 
beautiful  green  flame.  The  solution  is  blue  when 
diluted,  but  a  rich  emerald  green  when  concentrated,  or 
when  mixed  with  excess  of  hydrochloric  acid.  The 
anhydrous  chloride  absorbs  three  equivalents  of  ammo- 
nia, and  is  converted  into  a  blue  compound. 

Oxchlorides  of  Copper.  There  are  three  combina- 
tions of  the  chloride  and  oxide  of  copper,  containing  one 
equivalent  of  the  former  to  two,  three  or  four  equivalents 
of  the  latter. 

Brunswick  Green.  CuCl,3CuO,4HO,  is  the  most 
interesting  of  these  compounds.  This  well-known  pig- 
ment is  made  by  digesting  hydrated  oxide  of  copper  in 
a  solution  of  the  chloride,  or  more  commonly  by  exposing 
plates  of  copper  moistened  with  hydrochloric  acid  or  sal- 
ammoniac  to  the  action  of  the  atmosphere.  It  is  a  green 
powder,  soluble  in  acids  but  not  in  water.  On  the  appli- 
cation of  heat  it  loses  water  and  becomes  brownish  black. 

When  chloride  of  copper  is  precipitated  by  a  small 
quantity  of  potassa,  a  pale-green  powder  is  thrown 
down  having  the  composition  CuCl,2CuO,4HO.  Heated 
strongly  it  becomes  black,  all  the  water  being  driven  off, 


46  CHEMICAL  RELATIONS  OF  COPPER. 

leaving  CuCl,2CuO.  Kept  at  208°,  a  brown  com- 
pound is  left,  CuCl,2CuO,HO.  The  black  substance 
moistened  becomes  CuCl,2CuO,3HO. 

Double  Chlorides  The  double  chloride  of  copper  and 
ammonium,  CuCl,NH4Cl,2HO,  is  obtained  by  mixing 
saturated  solutions  of  chloride  of  ammonium  and  chloride 
of  copper,  or  by  precipitating  with  ammonia  a  solution 
of  chloride  of  copper  containing  excess  of  hydrochloric 
acid.  It  crystallizes  in  beautiful  blue  rhombs,  soluble 
in  water,  efflorescent  in  the  air,  changing  into  a  greenish- 
white  powder. 

When  hot  chloride  of  copper  is  saturated  with  ammo- 
niacal  gas,  ammonia-chloride,  CuCl.NH3,  is  formed, 
which  is  decomposable  by  water.  This  dissolves  a  biam- 
monia-chloride,  CuCl,2NH3,  which  crystallizes  in  dark- 
blue  prisms,  having  the  formula  CuCl,2NH3,HO.  A 
tri-ammonia-chloride,  CuCcl,3NH3,  also  exists. 

A  double  chloride  of  copper  and  potassium  is  formed  by 
mixing  strong,  hot  solutions  of  the  two  chlorides.  While 
cooling,  the  solution  deposits  blue  octahedra,  belonging 
to  the  quadratic  system,  and  having  the  formula  KC1, 
CuCl,2HO.  The  subchloride,  used  instead  of  the  chlo- 
ride, furnishes  a  double  salt,  crystallizing  in  anhydrous 
octahedra  of  the  regular  system. 

Bromide  of  Copper.  CuBr.  Oxide  of  copper  dis- 
solved in  hydrobromic  acid  and  evaporated,  forms  green 
crystals  of  the  form  CuBr,5HO,  which  by  heat  separate 
into  bromide  and  subbromide,  Cu2Br.  Dry  bromide 
absorbs  ammonia,  leaving  CuBr,5NH3.  There  are  several 
other  ammonia-bromides  and  a  basic  salt,  but  none  of 
any  particular  interest. 


CHEMICAL  RELATIONS  OF  COPPER.  47 

Diniodide  of  Copper.  Cu2L  When  a  solution  of 
iodide  of  potassium  is  added  to  another  of  blue  vitriol, 
one  half  the  iodine  separates,  sulphate  of  potassa  remains 
in  solution,  and  a  brownish-white  subiodide  of  copper, 
mixed  with  finely  divided  iodine,  is  precipitated.  The 
latter  is  washed  off  with  alcohol.  The  sub-iodide  is 
fusible  and  easily  decomposed  by  nitric  and  sulphuric 
acids  and  by  alkalies.  The  iodide  has  not  been  sepa- 
rated. A  blue  ammonia-iodide,  however,  exists  of  the 
formula  CuI,2NH3,HO. 

Sulfluoride  of  Copper.  Cu2,Fl3.  Hydrofluoric  acid 
brought  in  contact  with  hydrated  suboxide  of  copper 
converts  it  into  a  fusible  suLJuoride.  The  silico-sub- 
fluoride  3Cu2F1.2SiFl,  resembles  it  in  color  and  char- 
acter. 

Terfluoride  of  Copper.  CuFl3.  Hydrofluoric  acid 
forms  with  black  oxide  of  copper  a  blue  solution,  from 
which  this  fluoride  separates  in  crystals  containing  two 
equivalents  of  water.  It  forms  with  the  alkalies  and 
alumina,  green  soluble  double  salts.  An  oxyfluoride 
(CuFl,CuO,HO)  is  formed  by  treating  the  blue  fluoride 
with  hot  water. 

A  borcfluoride  is  obtained  by  decomposing  sulphate 
of  copper  with  borofluoride  of  barium.  It  separates  in 
blue  deliquescent  crystalline  needles  of  the  form  CuF, 
BF13. 

The  silico-fluoride  is  in  blue  prisms  containing  twenty- 
one  equivalents  of  water,  two  of  which  are  separated  by 
the  efflorescence  of  the  salt. 


48                     CHEMICAL  RELATIONS  OF  COPPER. 
AMPHID  SALTS.* OXYSALTS. 

SALTS  OF  THE  SUBOXIDE.  Salts  of  the  suboxide  are 
obtained  by  dissolving  the  suboxide  in  dilute  acids. 

Sulphite  of  the  Suboxide  of  Copper — Sulphite  of  Cop- 
per. Cu20,S02.  When  sulphurous  acid  is  poured  upon 
hydrated  oxide  or  carbonate  of  copper,  a  double  de- 
composition ensues,  which  may  be  understood  by  the 
formula  3CuO+2S02=CuO,S03+Cu20,S02.  Sulphate 
of  copper  is  formed  at  the  expense  of  one  part  of  the 
oxide  and  is  dissolved,  and  the  remaining  suboxide 
unites  with  the  residual  sulphurous  acid,  forming  the 
subsulphite  under  consideration.  It  is  also  obtained  by 
heating  a  mixture  of  sulphate  of  copper  with  sulphite  of 
soda. 

It  is  a  brilliant  red  crystalline  powder,  unchange- 
able when  dry,  soluble  in  hydrochloric  and  sulphurous 
acids  and  ammonia,  but  insoluble  in  water.  Boiling 
decomposes  it,  and  sulphuric  acid  exerts  the  same  action 
upon  it. 

*  This  term  is  derived  from  a.u^t,  "  both,"  and  used  to  denote  those 
salts  in  which  both  base  and  acid  are  double,  and  contain  the  same 
element.  Thus  sulphate  of  copper  is  written  CuO.S03,  and  is  regarded 
as  a  compound  of  oxide  of  copper  and  sulphuric  acid,  of  both  of  which 
oxygen  is  an  essential  constituent.  Such  salts  are  called  oxysalts,  but 
oxygen  is  not  the  only  simple  body  which  plays  this  part.  In  sul- 
pharseniate  of  potash,  for  example,  sulphuret  of  potassium  is  the  base, 
and  sulpharsenic  acid  the  acid  of  the  salt,  which  has  the  formula 
2Ks,AsS3.  The  latter  is  a  sulphacid,  the  former  a  sulpho-base,  and  the 
compound  a  sulpho-salt.  Selenium  and  tellurium  act  in  the  same  man- 
ner. To  include  these  salts  and  others  analogous  to  them  which 
may  be  discovered,  it  was  necessary  to  find  some  generic  term.  To 
meet  this  Berzelius  suggested  the  above  name,  which  at  present  seems 
perfectly  satisfactory. 


CHEMICAL  RELATIONS  OF  COPPER.  49 

There  is  an  insoluble  double  sulphite  of  copper  and 
potassa. 

Hyposulphite  of  Suboxide  of  Copper,  obtained  by 
treating  the  sulphate  with  hyposulphite  of  lime,  is  a 
colorless  solution.  It  forms  several  double  salts  with 
potassa  and  soda.,_ 

Silicate  of  Suboxide  of  Copper.  This  is  the  sub- 
stance which  forms  the  coloring  matter  of  red  glass.  It 
is  sometimes  found  in  the  quartz  which  surrounds  native 
copper. 

A  subacetate  of  copper  is  found  as  a  white  sublimate 
lining  the  upper  part  of  the  retort,  after  the  distilla- 
tion of  acetate  of  copper. 

Reactions  of  Salts  of  the  Suboxides.  The  soluble 
subsalts  have  colorless  solutions  from  which  the  fixed 
alkalies  throw  clown  the  base  as  a  reddish-yellow  pre- 
cipitate. Ammonia  produces  the  same  precipitate,  but 
rapidly  dissolves  it,  forming  a  colorless  solution,  which 
soon  becomes  blue  in  the  air,  from  absorption  of  oxy- 
gen and  consequent  change  of  the  suboxide  into  oxide. 
Sulphydric  acid  (sulphureted  hydrogen)  throws  down 
from  these  salts  the  black  sulphide  of  copper. 

For  the  study  of  these  reactions  the  subchloride  is  the 
proper  salt  to  select. 

SALTS  OF  THE  PROTOXIDE. 

Reactions  of  Salts  of  Slack  Oxide.  The  hydrated 
salts  of  the  black  oxide  with  colorless  acids  are  blue 
or  green,  the  anhydrous  salts  are  white.  They  are 
obtained  usually  by  dissolving  the  oxide  or  the  car- 
bonate in  acids. 
rv 


50  CHEMICAL  RELATIONS  OF  COPPER. 

Caustic  fixed  Alkalies  precipitate  a  voluminous,  pale 
blue,  hydrated  oxide  of  copper,  which,  as  we  have 
already  said,  changes  to  a  black,  heavy  anhydrous 
oxide  when  the  solution  is  boiled  over  it.  It  is  insolu- 
ble in  alkaline  solutions  when  they  are  dilute,  but  dis- 
solves in  them  when  concentrated,  giving  them  a  blue  tint. 

Ammonia  throws  down  the  same  precipitate,  but  a 
slight  excess  of  this  reagent  redissolves  it,  forming  a 
magnificent  blue  solution,  containing  a  double  salt  of 
copper  and  ammonia.  Caustic  potassa  precipitates  from 
this  solution  all  its  copper  as  hydrated  oxide. 

SulpTiydric  acid  and  the  sulphydrates  throw  down  the 
black  sulphide  of  copper.  This  is  insoluble  in  the  alka- 
line sulphides,  excepting  in  the  sulphide  of  ammonium, 
which  dissolves  it  to  a  very  slight  extent. 

The  carbonates  of  potash  and  soda  throw  down  a 
greenish-blue  precipitate,  which  is  a  mixture  of  the 
hydrated  oxide  and  the  carbonate. 

Ferrocyanide  of  potassium  throws  down  a  fine  ma- 
hogany or  chesnut-brown  precipitate.  In  extremely 
dilute  solutions  it  only  tinges  the  fluid  of  a  purplish- 
brown. 

Albumen  forms  with  copper  an  insoluble  yellowish- 
white  precipitate,  which  has  been  shown  by  Orfila  to  be 
inert,  so  that  albumen  may  be  used  as  an  antidote  in 
cases  of  poisoning  by  copper. 

Metallic  iron  or  zinc  throws  down  metallic  copper  as 
a  brown  powder  or  in  crystalline  flakes.  In  dilute  solu- 
tions these  reagents  are  only  tinged  with  a  superficial 
coating  of  copper. 

Borax,  and  vitreous  fluxes  generally,  fused  with  cop- 


CHEMICAL  RELATIONS  OF  COPPER.  51 

per  salts,  are  green  when  warm,  but  become  blue  on 
cooling.  If  a  bead  so  colored  be  heated  in  the  inner 
flame,  especially  after  a  little  tin  has  been  added  to  it, 
it  is  reduced,  and  shows  the  fine  ruby-red  of  the  sub- 
oxide.  "When  heated  a  long  time  it  is  reduced  to  metal. 
This  reduction  is  easily  accomplished  by  mixing  the 
substance  with  carbonate  of  soda  and  heating  it  upon 
charcoal.  The  bead  then  rubbed  up  with  water  in  a 
porcelain  or  glass  mortar  will  exhibit  little  red  spangles 
of  metallic  copper. 

The  delicacy  of  some  of  these  tests  is  remarkable.  A 
clean,  polished  rod  of  iron  is  stained  with  a  solution 
containing  only  one  part  of  copper  in  150,000  of  water. 
Iron  wire  is  best  adapted  for  this  test.  Steel  is  not  so 
sensitive.  The  iron  will  indicate  the  presence  of  copper 
in  a  still  weaker  solution  if  it  be  made  part  of  a  minia- 
ture galvanic  battery,  by  wrapping  a  coil  of  fine  plati- 
num wire  around  it.  SulpJiureted  hydrogen  gives  a 
brown  tint  in  a  solution  of  one  part  of  copper  in 
100,000  of  water.  Tincture  of  guiacum  gives  a  blue 
tint,  changing  to  green  when  only  one  part  is  diffused 
through  450,000  of  water.  Ferrocyanide  of  potassium 
colors  ten  gallons  of  water  containing  only  one  grain  of 
copper. 

Sulphate  of  Copper.  This  salt  is  a  common  pro- 
duct of  mines  of  sulphuret  of  copper.  The  ore  is 
oxydized  by  the  joint  action  of  air  and  moisture,  and 
the  water  which  trickles  over  it  washes  off  the  newly 
formed  sulphate.  This  natural  process  has  been  imi- 
tated by  manufacturers  who  calcine  the  native  or  arti- 
ficial sulphuret.  The  latter  is  obtained  by  heating  three 


52  CHEMICAL  RELATIONS  OF  COPPER. 

parts  of  copper  with  one  of  sulphur,  till  the  two  com- 
bine. The  roasting  is  sometimes  carried  on  in  the  same 
furnace  with  the  sulphuration.  The  fragments  of  old 
sheathing,  which  has  been  rendered  useless  by  the  cor- 
rosion of  salt  water,  are  heated  to  a  dull-red  in  a 
reverberatory  furnace,  the  doors  are  then  closed  and 
sulphur  thrown  in  from  above.  As  soon  as  the  com- 
bination has  taken  place,  the  doors  are  opened  to  admit 
air,  when  the  roasting  commences;  a  portion  of  sulphur 
burns  off,  and  the  rest  of  the  sulphurct  is  oxydized  to 
proto-sulphate  of  copper.  After  the  roasting  has  been 
completed,  the  remaining  sulphate  is  lixiviated.  When 
the  last-mentioned  plan  is  adopted,  the  sulphatized 
sheets  are  hung  in  boilers  filled  with  water  acidified 
with  sulphuric  acid,  till  the  sulphate  is  dissolved.  The 
sheets  are  then  returned  to  the  furnaces  and  the  same 
processes  are  repeated  till  the  copper  is  exhausted. 
The  addition  of  sulphuric  acid  increases  the  product 
by  dissolving  some  oxide  Avhich  has  escaped  the  acid  of 
the  roasted  sulphuret.  The  solutions  arc  evaporated 
and  crystallized. 

Obtained  in  either  of  these  modes,  sulphate  of  copper 
is  always  impure,  containing  more  or  less  iron,  and 
sometimes  traces  of  other  metals.  The  quantity  of  iron 
contained  in  the  sulphate  made  from  the  roasted  ore 
varies  greatly  with  the  temperature  at  which  it  has  been 
calcined.  At  a  very  low  heat  sulphate  of  iron  only  is 
formed;  at  a  bright  red  this  salt  is  decomposed,  and  to 
a  considerable  extent  rendered  insoluble.  If  then  the 
heat  be  sufficiently  raised,  this  impurity  will  be  very 
greatly  diminished,  though  not  entirely  god  rid  of. 


CHEMICAL  KELATIONS  OF  COPPER.  53 

In  the  arts  it  is  not  always  necessary  to  have  a  blue 
vitriol  entirely  free  from  iron.  If  it  be  desired,  how- 
ever, its  purification  may  be  accomplished  by  heating  it 
to  a  dull  redness  with  access  of  air,  when  nearly  all  the 
iron  will  be  rendered  insoluble,  and  a  portion  of  the 
copper  too  will  be  left  behind  as  oxide.  On  lixiviating 
the  mass  we  obtain  a  sulphate  of  copper,  containing 
little  more  than  a  trace  of  iron.  The  residuum  may  be 
treated  with  sulphuric  acid  and  the  copper  obtained 
from  it  by  precipitation  with  scraps  of  metallic  iron. 

Another  method  of  preparing  it  is  to  moisten  copper- 
filings  with  sulphuric  acid,  to  expose  them  to  the  atmos- 
phere, and  to  continue  this  process  till  the  copper  is 
entirely  converted  into  sulphate. 

A  modification  of  the  process  which  yields  an  excel- 
lent article  is  the  following.  The  best  commercial 
copper  is  treated  with  sulphuric  acid  diluted  with  one- 
half  its  weight  of  water ;  sulphurous  acid  is  disengaged, 
the  copper  being  oxidated  at  the  expense  of  the  oil  of 
vitriol,  and  sulphate  of  copper  is  formed.  To  rid  this 
of  a  little  sulphate  of  iron,  it  is  evaporated  to  dryness, 
and  a  little  nitric  acid  is  added  towards  the  close  of  the 
operation.  This  converts  the  iron  into  sesquioxide,  which 
is  insoluble  in  water.  The  iron  remains  behind  as  basic 
sesquisulphate,  when  the  dry  mass  is  lixiviated ;  only  a 
very  small  portion  of  it  entering  into  the  solution.  It 
is  said  that  this  is  totally  precipitated  by  boiling  with 
carbonate  or  hydrated  oxide  of  copper. 

This  salt  is  also  procured  in  large  quantities  in  the 
process  of  parting  gold  and  silver,  and  in  the  refining  of 
old  silver  coins.  In  these,  independently  of  the  copper 


54  CHEMICAL  RELATIONS  OF  COPPER. 

contained  in  the  coins  themselves,  a  large  quantity  is 
furnished  by  the  liquor  which  floats  over  the  precipi- 
tated silver,  resulting  from  the  solution  of  the  copper 
used  to  precipitate  that  metal. 

Sulphate  of  copper  is  obtained  perfectly  pure  by  dis- 
solving pure  oxide  in  pure  sulphuric  acid. 

Pure  hydrated  sulphate  of  copper  is  an  azure  blue  salt, 
crystallizing  in  elongated  rhombs,*  of  the  doubly  oblique 
rhombic  or  triclinate  system.  These  contain  32  parts 
of  oxide  of  copper,  32  of  sulphuric  acid,  and  36  of 
water  in  the  hundred  parts,  and  may  be  expressed  by 
the  formula  Cu,S03,5HO.  A  small  quantity  of  iron  is 
recognized  by  the  greenish  cast  it  gives  to  the  crystals, 
especially  to  their  effloresced  surfaces.  The  presence  of 
iron  and  zinc  in  the  salt  is,  however,  better  detected  by 
a  brief  and  simple  analytical  process.  A  stream  of  sul- 
phureted  hydrogen  is  passed  through  a  solution  of  the 
salt,  previously  acidified,  until  all  the  copper  is  precipi- 
tated as  sulphide.  This  is  filtered  off,  the  filtrate  boiled 
with  the  addition  of  a  few  drops  of  nitric  acid,  and  after 
it  has  cooled  the  iron  is  precipitated  by  excess  of  ammo- 
nia. After  separating  the  sesquioxide  of  iron  by  filtra- 
tion, the  clear  liquid  is  tested  for  zinc  with  sulphide  of 
ammonium,  which  throws  down  a  white  sulphide  of  zinc. 

Exposed  to  a  dry  atmosphere  the  salt  effloresce 
parting  with  two  equivalents  of  water.  At  212°  it  loses 
four  equivalents,  but  retains  the  fifth  with  more  tena- 

*  These  crystals  are  sometimes  opaque  in  spots,  in  consequence  of 
some  of  the  sulphate  being  deposited  without  its  water  of  crystalliza- 
tion. This  is  especially  the  case  when  they  are  deposited  from  a 
strongly  acid  solution. 


CHEMICAL  RELATIONS  OF  COPPER.  55 

city.  For  this  reason,  the  last  equivalent  has  been 
reckoned  by  some  chemists  as  basic  water,  the  formula 
CuO,S03,HO+4HO,  has  been  assigned  to  it.  At  from 
390°  to  430°  this  water  of  constitution  is  expelled,  leav- 
ing the  anhydrous  salt  a  dirty-white  pulverulent  mass. 
At  a  still  higher  heat  it  is  decomposed,  being  resolved 
into  sulphurous  acid  and  oxygen,  which  escape,  and 
black  oxide  of  copper  which  remains  behind.  The 
anhydrous  salt  has  a  strong  affinity  for  water,  com- 
bining with  it  very  energetically  and  resuming  the  blue 
tint  of  the  hydrated  salt. 

The  crystallized  sulphate  is  soluble  in  four  parts  of 
cold  and  two  of  boiling  water.  The  solution  is  blue  with 
an  acid  reaction,  and  an  unpleasant  metallic  taste.  It 
is  insoluble  in  alcohol.  Like  the  other  salts  of  copper, 
it  is  poisonous  to  men  and  animals. 

"According  to  Kane,  crystallized  sulphate  of  copper, 
when  dissolved  in  hydrochloric  acid,  causes  considerable 
depression  of  temperature,  and  yields  a  green  liquid, 
from  which  chloride  of  copper  alone  is  deposited  upon 
evaporation,  provided,  not  less  than  one  equivalent  of 
the  acid  has  been  used  for  each  equivalent  of  salt  ; 
in  allowing  the  crystals  to  remain  for  some  time  with 
the  mother-liquor,  which  contains  all  the  sulphuric  acid, 
crystals  of  blue  vitriol  are  reproduced.  Powdered  crys- 
tals of  sulphate  of  copper  eagerly  absorb  hydrochloric 
acid  gas,  evolving  much  heat  and  losing  water  ;  a  green 
mass  is  obtained,  which  is  very  deliquescent  and  fumes 
in  air." — Abel  $  Bloxam. 

Sulphate  of  copper  combines  in  various  proportions 
with  the  isomorphous  sulphates  of  zinc,  iron  and  copper. 


56  CHEMICAL  RELATIONS  OF  COPPEE. 

With  iron  especially,  this  combination  takes  place  with 
great  readiness.  Mixed  solutions  of  the  two  sulphates 
crystallize  together,  and  the  resulting  crystals  contain 
variable  proportions  of  the  three  salts.  A  crystal  of  sul- 
phate of  copper  grows,  indeed,  as  readily  in  a  solution 
of  sulphate  of  iron  as  in  its  own  mother-liquor.  It  may 
be  dipped  alternately  into  concentrated  solutions  of  the 
two  salts,  and  it  will  continue  to  increase,  the  layers  of 
the  green  and  blue  vitriol  remaining  quite  distinct,  and 
being  easily  distinguished  by  their  color.  Sulphate  of 
magnesia  also  forms  double  salts  with  sulphate  of  cop- 
per. In  all  these  cases,  the  double  salts  contain  five 
equivalents  of  water  when  the  copper-salt  is  in  excess, 
and  seven  when  the  other  sulphate  predominates. 

The  specific  gravity  of  this  salt  is  2.274,  water  being 
the  standard  of  unity.  Its  water  of  constitution  is  occa- 
sionally replaced  by  an  alkaline  sulphate,  a  crystallizable 
double  salt  being  the  result. 

Uses.  Sulphate  of  copper  is  largely  employed  in 
medicine.  It  is  used  as  an  emetic,  a  tonic,  an  astrin- 
gent, a  styptic,  and  a  feeble  escharotic.  In  dyeing  it  is 
employed  to  develop  the  various  colors  of  which  copper 
is  the  basis,  and  as  a  reserve  in  the  cold  indigo  vat.  In 
the  electrotype  process  it  is  used  for  taking  copies  of 
medals  in  metallic  copper.  It  is  the  salt  usually  selected 
by  the  manufacturer  of  blue  verditer,  Scheele's  green,  and 
other  pigments  of  copper.  It  is  sometimes  mixed  with 
copperas  in  making  ink ;  but  this  is  a  very  bad  practice, 
as  it  does  not  materially  improve  the  color  of  the  ink, 
and  renders  it  very  corrosive  in  its  action  on  steel  pens. 
Anhydrous  sulphate  of  copper  is  used  to  deprive  alcohol 
of  water. 


CHEMICAL  RELATIONS  01'  COPPEll.  57 

Basic  Sulphates.  Three  have  been  described,  of  the 
formulas,  3CuO,S03,2HO;  4CuO,S03,4HO;  and  5CuO, 
S035HO.  The  second  of  these  is  the  mineral  brochantite. 
They  are  prepared  by  precipitating  the  sulphate  just 
described  with  a  small  quantity  of  alkali,  by  digesting 
fresh  carbonate  or  hydrate  of  copper  in  a  solution  of  blue 
vitriol,  or  by  exposing  ammonia-sulphate  to  the  air. 
They  are  pale  green,  insoluble,  easily  decomposed  by 
heat  into  water,  sulphate,  and  oxide  of  copper.  Kane 
says  that  by  precipitating  blue  vitriol  with  caustic 
potassa,  he  obtained  another  basic  salt,  the  composition 
of  which  is,  8CuO,S03,12HO. 

Ammonia  Sulphates  of  Copper.  There  are  several 
double  salts  of  copper  formed  with  ammonia  and  potassa. 
The  ammoniacal  double  salts  vary  much  in  color  and 
composition. 

When  solutions  of  the  two  sulphates  of  copper  and 
ammonia  are  mixed  and  duly  concentrated,  we  obtain 
light  blue,  very  soluble  crystals  of  the  formula  NH40 
S03,CuOS03,6HO.  When  carbonate  of  ammonia  and 
sulphate  of  copper  (three  parts  of  the  foianer,  and  two 
of  the  latter)  are  rubbed  together  in  a  mortar,  carbonic  acid 
is  evolved,  the  mass  becomes  blue  and  moist,  and  another 
double  salt,  the  ammoniated  copper  of  the  pharmacopoeia  is 
formed.  When  a  strong  solution  of  blue  vitriol  is  treated 
with  water  of  ammonia  till  the  insoluble  sub-salt  first 
thrown  down  is  all  dissolved,  we  obtain  an  ultra-marine 
blue  solution,  from  which  by  gradual  evaporation,  cold, 
or  the  addition  of  alcohol,  blue  prisms  of  ammonia-sul- 
phate of  copper  separate.  Their  formula  is  CuO,S03, 
2NH3,HO.  They  are  soluble  in  2J  parts  of  water, 


58  CHEMICAL  RELATIONS  OF  COPPER. 

and  decompose  in  the  air.  At  300°  they  become  apple- 
green,  having  parted  with  their  water  and  one  equivalent 
of  ammonia,  and  at  400°  one-half  of  the  remaining  alkali 
is  expelled.  Anhydrous  sulphate  of  copper  absorbs 
53.97  per  cent,  of  dry  ammoniacal  gas,  forming  a  soluble 
blue,  the  constitution  of  which  is  represented  by  the 
formula  2Cu,S03,5NH3. 

Sulphate  of  Copper  and  Potassa  is  a  light  blue  salt, 
formed  by  crystallizing  the  mixed  solutions  of  the  sul- 
phates. It  is  KOS03Cu,S03,6HO.  It  loses  two 
equivalents  of  water  at  212°,  and  deposits  a  green  basic 
double  salt  on  cooling.  The  double  sulphate  with  soda 
is  formed  in  the  same  manner  from  the  blue  vitriol  and 
bi-sulphate  of  soda.  A  salt  composed  of  the  sulphates 
of  copper,  soda  and  magnesia,  may  be  formed  by  mix- 
ture and  crystallization. 

Hyposulphate  of  Copper.  CuOS203,4HO.  When 
sulphate  of  copper  is  exactly  decomposed  by  hyposul- 
phate  of  baryta  and  the  solution  concentrated,  rhombic 
prisms  soluble  in  water  are  obtained,  from  which  a  small 
quantity  of  ammonia  precipitates  a  basic  hyposulphate, 
and  with  which  an  excess  of  the  same  reagent  forms  a 
double  salt  which  crystallizes  in  azure  square  tables, 
difficult  of  solution,  permanent  in  the  air,  and  composed 
of  CuOS205,2NH3. 

Phosphate  of  Copper.  Phosphate  of  soda  throws 
down  from  a  solution  of  cupreous  salt,  this  compound  as 
a  greenish  powder,  insoluble  in  water,  soluble  in  acids, 
becoming  brown  by  heat.  A  number  of  basic  phosphates 
have  been  found  native. 

The  phosphate  and  hypophosphate  of  copper  possess 
no  particular  interest. 


CHEMICAL  RELATIONS  OF  COPPER.  59 

Nitrate  of  Copper.  When  nitric  acid  is  poured  upon 
metallic  copper,  violent  action  takes  place,  even  in  the 
cold — strong  effervescence  ensues,  heat  is  evolved, 
copious,  dense,  red  fumes  rise,  and  a  blue  solution  is 
obtained.  The  reaction  will  be  understood  by  a  glance 
at  the  formula.  Thus,  3Cu+4N05=3CuON05+N02. 
The  deutoxide  of  nitrogen,  as  it  rises  through  the  atmos- 
phere, absorbs  oxygen,  and  forms  the  red  fumes  of  nitrous 
acid.  To  obtain  the  solution,  the  use  of  concentrated 
nitric  acid  must  be  avoided,  or  a  green  insoluble  basic 
salt  will  subside. 

The  crystals,  obtained  from  this  solution  at  low  temper- 
atures, contain  six  equivalents  of  water ;  those  procured  at 
high  temperatures,  only  three.  They  are  fine  blue  prisms, 
those  containing  six  equivalents  of  water  being  paler 
than  those  which  have  only  three.  They  deflagrate  on  red 
hot  coals  and  behave  generally  like  other  nitrates.  They 
oxidate  some  metals  very  powerfully.  Powdered,  moist- 
ened with  a  very  small  quantity  of  water,  and  wrapped 
in  tin  foil,  spontaneous  ignition  takes  place. 

Anhydrous  nitrate  of  copper  has  been  obtained.  When 
the  crystals  are  heated,  they  lose  water  and  nitric  acid, 
and  are  converted  into  a  sparingly  soluble  basic  nitrate, 
of  the  formula  4CuO,N05.  If  the  heat  is  pushed,  all 
the  acid  is  driven  off  and  oxide  of  copper  left. 

With  a  small  quantity  of  ammonia  the  basic  salt  is 
precipitated,  and  with  a  larger  proportion  it  is  dissolved, 
forming  a  blue  solution,  which  deposits  crystals  of  the 
constitution,  CuON05,2NH3.  By  passing  ammoniacal 
gas  into  a  concentrated  solution  of  nitrate  of  copper, 
and  carefully  evapoi'ating,  a  compound  of  amide  of  cop- 


60  CHEMICAL  RELATIONS  OF  COPPEK. 

per  with   nitrate   of  ammonia   (CoNH2,NH4ON05)    is 
formed. 

CARBONATES  OF  COPPER. 

The  native  carbonates  will  be  described  in  the  next 
chapter.  Of  the  artificial  carbonates,  the  best  knovm 
is  the 

Bibasie  Carbonate  of  Copper,  2CuOC02,HO.  It 
is  obtained  by  treating  a  copper  solution  with  an  alkaline 
carbonate,  as  a  bulky,  blue,  gelatinous  precipitate.  If 
this  be  gently  heated  with  the  supernatant  liquor,  it 
assumes  a  granular  form  and  a  green  color,  and  in  this 
condition,  is  sold  as  a  pigment  under  the  name  of  min- 
eral green.  If  long  boiled  with  the  solution  from  which 
it  has  been  precipitated,  all  the  carbonic  acid  is  gradu- 
ally driven  off,  and  black  oxide  of  copper  is  left. 

An  Ammoniacal  Carbonate  of  Copper,  CuO,C4H303, 
HO,  has  been  obtained  in  fine  blue  needles,  by  dissolv- 
ing the  bibasic  carbonate  in  ammonia,  and  adding  al- 
cohol. 

Double  carbonates  with  potassa  and  soda  may  be  crys- 
tallized from  a  solution  of  the  bibasic  carbonate  in  the 
bicarbonate  of  either  of  the  bases. 

Borate  of  Copper  is  a  pale  green  powder,  slightly  solu- 
ble in  water,  fusing  to  a  green  glass.  It  may  be  obtained 
by  melting  oxide  of  copper  and  borax  together,  and  dis- 
solving out  the  alkaline  salt  with  Avater. 

Silicate  of  Copper  is  green,  and  has  been  obtained 
artificially  by  fusing  oxide  of  copper  with  glass. 

The  salts  with  the  halogens  are  of  no  special  interest 
nor  importance. 


CHEMICAL  RELATIONS  OF  COPPER.  61 

Tlft  chlorate,  formed  by  direct  union  of  the  oxide  with 
chloric  acid,  forms  green  deliquescent  crystals.  The 
perchlorate,  formed  in  the  same  way,  is  in  blue  deliques- 
cent crystals.  Like  other  chlorates  and  perchlorates, 
they  deflagrate  with  red  hot  charcoal.  The  iodate, 
obtained  in  the  same  manner,  or  by  double  decompo- 
sition, is  sparingly  soluble  in  water.  The  bromate  is  in 
sea-green  crystals. 

ACETATES    OF   COPPER. 

There  are  several  combinations  of  oxide  of  copper  with 
acetic  acid.  One  of  these  is  neutral ;  the  rest  are  basic. 

Neutral  Acetate  of  Copper.  CuOC4H303,HO.  This 
salt  is  obtained  by  dissolving  oxide  of  copper  or  verdi- 
gris in  acetic  acid,  or  by  precipitating  acetate  of  lead 
with  an  equivalent  of  sulphate  of  copper.  By  crys- 
tallizing any  of  the  solutions  thus  obtained,  the  salt 
separates  in  dark-green,  oblique  rhombic  prisms,  with 
oblique  terminal  planes.  It  is  soluble  in  13.4  parts  of 
cold  and  5  of  boiling  water.  In  the  air,  it  burns  with  a 
green  flame,  and  when  distilled  in  close  vessels  it  gives 
off  the  various,  products  of  the  decomposition  of  vinegar, 
and  then  strong  acetic  acid,  leaving  behind  finely  divided 
and  easily  inflammable  metallic  copper.  Mixed  with 
honey,  sugar,  &c.  it  is  decomposed,  small,  red,  octohe- 
dral  crystals  of  suboxide  of  copper  subsiding,  and  formic 
acid  remaining  in  the  liquid. 

If  the  solution  be  made  with  dilute  acid  and  crystal- 
lized at  a  low  temperature,  the  crystals  are  blue  four- 
sided  prisms,   containing  5  equivalents  of  water,  4  of 
which  are  lost  when  the  salt  is  heated. 
6 


62  CHEMICAL  RELATIONS  OF  COPPER. 

Commercially,  this  salt  is  prepared  by  dissolvin^'in.  a 
copper  kettle,  one  part  of  verdigris  in  two  of  distilled  vine- 
gar, with  the  aid  of  a  slight  heat  and  constant  agitation 
with  a  wooden  spatula.  As  soon  as  the  liquid  has  attained 
the  greatest  possible  intensity  of  color,  it  is  decanted 
into  well  glazed  earthen  vessels,  and  fresh  vinegar  is 
added  to  the  residue.  If  this  is  not  sufficient  to  saturate 
the  acid,  more  verdigris  is  added.  The  clear  solution 
is  then  evaporated  to  a  syrupy  consistence,  and  crystal- 
lized around  sticks  in  a  room  heated  with  stoves.  As 
thus  obtained,  the  crystals  are  blue  and  rhomboidal. 

Basic  Acetates  of  Copper — Bibasic  Acetate  of  Copper. 
Verdigris.  The  formula  for  this  salt,  as  commonly  writ- 
ten, is  CuO,C4H303  CuO,HO,5HO,  which  assumes  it 
to  be  a  compound  of  the  blue  neutral  acetate  with  the 
hydrated  oxide.  In  reality,  however,  it  is  a  very  varia- 
ble salt,  and  the  analysis  does  not  always  correspond  with 
this  theoretical  constitution. 

It  is  obtained  by  exposing  sheets  of  metallic  copper  to 
the  mash  of  the  grape,  while  it  is  undergoing  the  acetous 
fermentation,  or  by  wrapping  them  in  cloths  moistened 
with  acetic  acid.  There  is  a  difference  in  the  color  of 
the  two  products,  that  obtained  by  the  former  process 
being  blue,  while  the  result  of  the  latter  operation  is 
green.  It  is  a  hard  tough  mass,  varying  in  color  from 
a  blue  to  a  green,  and  decomposed  by  cold  water  into 
two  salts,  presently  to  be  described. 

Tests.  It  should  be  dry,  of  a  clear  bluish  green  tint, 
soluble  in  ammonia  and  diluted  acetic  acid,  and  when 
ignited  in  a  close  vessel,  it  should  leave  a  residue  of 
metallic  copper  mixed  with  carbon. 


CHEMICAL  RELATIONS  OF  COPPER.  63 

Sesquibasic  Acetate  of  Copper.  3Cu02(C4H303),6HO. 
When  verdigris  is  treated  with  warm  water,  it  is  decom- 
posed, and  a  blue  amorphous  mass,  the  sesquibasic  acetate 
remains  behind,  after  spontaneous  evaporation.  Should 
the  solution  have  been  previously  mixed  with  alcohol, 
this  same  salt  is  obtained  in  crystalline  scales.  When 
heated  to  the  boiling  point,  a  concentrated  solution 
deposits  a  liver-brown  powder. 

Tribasic  Acetate  of  Copper.  3CuOC4H303,3HO.  When 
verdigris  is  exhausted  of  its  soluble  salts  by  digestion  in 
water,  or  when  a  solution  of  the  neutral  acetate  is  di- 
gested with  hydrated  oxide  of  copper,  a  light  green 
tasteless  powder,  the  tribasic  acetate,  is  obtained.  It 
is  the  most  permanent  of  the  acetates  of  copper,  losing 
no  water  at  212°.  Boiled  with  water  it  undergoes  the 
same  decomposition  as  the  last  named  salt,  the  neutral 
salt  being  found  in  the  solution.  Heated  in  the  open 
air  it  burns  with  feeble  deflagration. 

Hyperbasic  Acetate  of  Copper.  The  formula  for  this 
salt  has  been  written,  48CuO,C4H303,12HO ;  but  it 
may  well  be  doubted  if  there  be  any  definite  compound 
of  the  kind.  It  is  probably  a  combination  of  the  oxide 
with  some  of  the  other  acetates.  It  is  deposited  as  a 
liver-brown  powder  when  any  of  the  other  acetates  is 
boiled  with  water.  When  dry  it  is  black  and  slightly 
soluble  in  water. 

Commercial  Verdigris,  is  a  variable  compound  of  the 
above  named  acetates.  The  greener  varieties,  according 
to  Berzelius,  are  principally  made  up  of  the  sesquibasic 
acetate,  while  the  bibasic  salt  is  the  chief  component  of 
the  blue  varieties. 


64  CHEMICAL  RELATIONS  OF  COPPER. 

It  is  made  in  the  south  of  France,  by  exposing  copper 
sheets  to  the  action  of  the  fermenting  residue  of  the 
grapes,  the  hulls,  &c.,  which  remain  after  the  expression 
of  the  must.  This  refuse  is  put  into  earthen  vessels, 
covered  with  lids  and  surrounded  by  straw  mats  to 
retain  the  heat.  Fermentation  soon  begins  and  the 
temperature  rises.  The  proper  time  for  commencing 
the  operation  is  determined  by  introducing  a  slip  of 
copper  as  a  test  into  the  fermenting  mash.  This  is 
allowed  to  remain  twenty-four  hours,  when,  if  it  be 
covered  with  uniform  green  layer  concealing  the  whole 
surface  of  the  copper,  all  is  ready  for  commencing  the  man- 
facture.  If,  however,  drops  of  liquid  remain  on  the 
surface  of  the  metal,  thfe  heat  is  considered  to  be  insuffi- 
cient and  the  materials  are  allowed  to  ferment  another 
day. 

fSlips  of  copper,  6  inches  long  by  3  broad,  and  weigh- 
ing about  4  ounces,  having  been  well  beaten  upon  an 
anvil,  to  remove  all  scales,  consolidate  the  metal  and 
give  it  a  smooth  hard  surface,  are  now  heated  over  a 
charcoal  fire,  and  introduced  into  earthen  vessels  in 
alternate  layers  with  the  fermenting  materials,  the  top 
and  bottom  strata  being  composed  of  the  grape  refuse. 
From  thirty  to  forty  pounds  of  copper  are  put  into  each 
vessel,  the  whole  covered  up  with  the  straw  mats  and 
left  at  rest.  In  from  ten  to  twenty  days  the  vessels  are 
opened  and  the  plates  examined,  when,  if  they  are 
covered  with  glossy  isolated  crystals,  they  are  placed 
upright  to  drain,  in  a  corner  of  the  cellar,  upon  a 
wooden  floor.  After  two  or  three  days  they  are  moist- 
ened by  being  dipped  into  water  or  spoiled  wine,  and 


CHEMICAL  RELATIONS  OF  COPPER.  65 

then  returned  to  the  fermenting  vats  in  the  same  order 
as  before.  This  operation  is  performed  every  week  for 
six  or  eight  times. 

In  consequence  of  this  treatment,  the  plates  swell, 
and  become  invested  with  a  green  layer  of  verdigris, 
which  is  removed  with  a  knife.  In  this  condition,  it  is 
called  fresh  or  humid,  and  five  or  six  pounds  of  it  (i.  e. 
about  16  per  cent.)  are  obtained  from  each  vessel.  It 
is  dried  by  kneading  it  in  wooden  troughs  and  suspend- 
ing it  in  leathern  bags  where  it  can  be  fully  exposed  to 
the  action  of  the  sun  and  air.  It  loses  about  half  its 
weight,  and  becomes  so  hard  that  a  knife,  driven  through, 
the  bag,  cannot  pierce  the  loaf  of  verdigris. 

A  purer  variety  is  made  in  some  parts  of  France  and 
in  England,  by  stratifying  the  copper  sheets  with  layers 
of  cloth  soaked  in  acetic  or  common  pyroligneous  acid, 
in  wooden  boxes.  The  cloths  are  moistened  with  acid 
every  three  days,  until  small  crystals  make  their  appear- 
ance, which  takes  place  in  about  twelve  days.  Tiiey  are 
then,  as  in  the  last  described  process,  moistened  with 
water  every  week,  the  cloths  removed,  and  a  small  space 
left  between  the  plates  for  circulation  of  air.  The  ope- 
ration is  finished  in  five  or  six  weeks. 

This  substance  is  also  made  by  putting  rolls  of  sheet 
copper  in  vessels  containing  vinegar,  in  the  same  manner 
as  plates  of  lead  are  treated  in  the  manufacture  of 
white  lead. 

Uses.     Verdigris  has  extensive  applications  in  the 

arts.     It  is  used  as  a  pigment  in  oil  painting,  and  as 

the  basis  of  other  pigments  hereafter  to  be  mentioned. 

It  is  also  employed  in  lacquering,  in  bronzing  copper, 

6* 


66  CHEMICAL  RELATIONS  OF  COPPER. 

in  calico  printing  as  a  resist-paste,  in  dyeing,  especially 
the  dyeing  of  hats.  The  neutral  acetate  is  used  as  a 
green  pigment.  It  was  formerly  employed  in  the  manu- 
facture of  concentrated  acetic  acid.  It  has  the  same 
applications  to  dyeing  and  calico  printing,  as  the  common 
verdigris. 

ARSENITES  OF  COPPER. 

ScJieeles  Grreen.  When  neutral  salts  of  arsenious  acid 
and  of  copper  are  mixed,  a  fine  green  precipitate  falls. 
This  is  largely  employed  as  a  pigment.  It  forms  that 
peculiar  delicate  green  so  much  used  by  paper  stainers, 
and  has  been  applied  to  dyeing  and  calico  printing,  by 
effecting  the  decomposition  upon  the  fabric  to  be  tinted. 

It  is  made  on  the  large  scale  by  dissolving  3  parts  of 
carbonate  of  potassa  and  1  of  arsenious  acid  in  14  parts  of 
water,  and  by  gradually  adding  this  while  hot  to  a  boil- 
ing solution  of  3  parts  of  sulphate  of  copper  in  40  parts 
of  watqr,  the  mixture  being  constantly  stirred.  The 
exact  hue  of  green  may  be  modified  by  altering  the 
quantity  of  arsenious  acid. 

Schweinfurtli  Grreen.  When  boiling  solutions  of  ace- 
tate of  copper  and  arsenious  acid  are  mixed,  a  bulky  olive 
green  precipitate  is  immediately  produced.  If  this  be 
boiled  in  the  supernatant  liquid,  it  changes  its  form  and 
color,  becoming  a  dense  granular  powder  of  a  beautiful 
green  tint.  The  same  alteration  takes  place  in  the  cold, 
if  time  enough  be  allowed  for  the  reactions.  It  is  said 
that  the  best  result  is  obtained  by  adding  to  the  hot 
mixed  solution  its  own  bulk  of  cold  water  and  allowing 
it  to  stand,  until  the  desired  color  is  obtained,  in  a  glass 
globe  filled  up  to  the  neck  with  the  mixture.  The  com- 


CHEMICAL  RELATIONS  OF  COPPER.  67 

mercial  formula  given  by  Kastner,  as  quoted  by  Ure,  is 
as  follows : — For  8  parts  of  arsenious  acid,  take  from  9 
to  10  of.  verdigris;  diffuse  the  latter  through. water  at 
120°  F.,  and  pass  the  pap  through  a  sieve ;  then  add 
the  arsenical  solution  and  set  the  mixture  aside  till  the 
reaction  of  the  ingredients  shall  produce  the  desired 
hue.  If  a  yellowish  tint  is  required,  more  arsenious 
acid  must  be  used.  By  digesting  Scheele's  green  in 
acetic  acid,  a  variety  of  Schweinfurth  green  may  be 
obtained. 

This  is  a  richer  pigment  than  the  last  named.  It  is 
useless  to  say  that  they  are  both  very  deadly  poisons, 
and  the  fact  is  only  mentioned  here  to  caution  the 
reader  against  the  green  candies  sold  by  our  confec- 
tioners, many  of  which  are  colored  with  Scheele's  green. 

There  is  another  arsenite  of  copper,  2CuOAs03, 
which  is  precipitated  by  neither  acids  nor  alkalies,  and 
which  yields  a  yellowish  green  salt  on  evaporation.  It 
is  made  by  digesting  the  oxide  or  the  carbonate  of 
copper  in  arsenious  acid. 

SULPHO-SALTS. 

A  SubsulpJwphosphite  of  Copper  is  formed  when  bisul- 
phide of  copper  is  treated  with  sulphide  of  phosphorus, 
and  gently  warmed  in  a  current  of  hydrogen.  It  is  a 
yellow  powder  of  the  composition  2Cu2S,PS3.  By 
heating  this,  two  equivalents  of  sulphur  are  driven  off, 
leaving  2Cu2S,PS. 

The  liyposulphopliosphite  (CuS,PS)  is  obtained  like 
the  last  compound  by  using  the  sulphide  of  copper 
instead  of  the  bisulphide.  Various  salts  are  formed 
from  it  by  decomposing  it  through  the  agency  of  heat. 


CHAPTER  II. 

ORES     OF     COPPER. 

THE  minerals  into  which  copper  enters  as  an  essen- 
tial ingredient  are  both  numerous  and  important,  but 
lie,  for  the  most  part,  out  of  the  range  of  a  book  like 
this.  The  working  ores,  as  they  are  termed  by  smelters, 
may  be  reduced  to  certain  classes  possessing  distinct 
outlines. 

Native  copper,  though  not  an  ore  of  copper  in  the 
strict  mineralogical  sense  of  the  word  ore,  has,  never- 
theless, a  place  in  the  smelter's  classification  and  con- 
stitutes a  class  by  itself.  The  second  class  comprises 
the  native  oxides  and  chlorides  of  copper.  The  third 
class  is  occupied  by  the  combinations  of  copper  with 
sulphur,  selenium,  arsenic  and  antimony.  The  silicates 
form  the  fourth  class,  and  the  fifth  class  is  taken  up 
with  the  remaining  oxysalts  of  this  metal. 

CLASS  I. 

Native  Copper  may  exist  either  crystallized,  amor- 
phous or  in  various  imitative  forms.  When  crystallized, 
it  belongs  to  the  monometric,  tesseral  or  cubic  system  of 
crytallographers ;  that  is  to  say,  whatever  may  be  the 
form  of  any  given  crystal,  it  is  in  every  case  a  modifica- 
tion of  a  cube,  and  can  be  referred  to  that  figure.  The 
forms  commonly  enumerated  arc  the  cube,  the  octahe- 


ORES  OF  COPPER.  69 

dron,  the  rhombic  dodecahedron,  the  twenty-four  hedron 
and  the  fourxsix  hedron,  or  cube  replaced  on  every  side 
by  a  four-sided  pyramid.  I  have  also  seen  obscure  pen- 
tagonal dodecahedral  crystals  and  every  possible  modifi- 
cation and  combination  of  these  various  forms.  Very 
often  the  matrix  in  which  it  is  contained  impresses  its 
own  crystalline  form  upon  the  copper,  so  that  the  metal 
is  covered  Avith  indentations  faithfully  copying  the  pro- 
jections of  the  crystals  among  which  it  lies  embedded. 
As  this  occurs  sometimes  in  masses  which  are  covered 
with  the  proper  crystals  of  copper,  it  constitutes  quite  a 
puzzling  phenomenon  to  the  beginner  in  crystallography. 

One  of  the  most  common,  and  at  the  same  time  most 
beautiful  forms  of  this  metal,  is  that  in  which  it  is  dif- 
fused through  the  rock  in  a  branching,  arborescent  form, 
so  that  it  resembles  a  great  metallic  lichen.  Often  it 
will  be  found  presenting  this  irregular  plant-like  form 
on  one  side,  while  on  the  other  it  is  covered  with  fine 
crystals  of  the  forms  already  described.  It  is  also  found 
in  great  masses,  in  thin,  films,  and  in  broad  sheets. 

It  is  soft  enough  to  be  cut  with  a  knife,  its  hardness 
varying  according  to  the  commonly  received  standard, 
from  2.5  to  3.  Its  specific  gravity,  when  pure,  is  8.74. 
It  possesses  the  color  and  lustre  of  fused  copper,*  and 
like  it  is  ductile  and  malleable. 

Its  behavior  with  chemical  reagents  is  of  course  iden- 
tical with  that  of  metallic  copper,  however  obtained. 
Before  the  blow-pipe  it  fuses,  becoming  covered  with  a 
coating  of  black  oxide.  It  dissolves  rapidly  in  nitric 
acid,  with  effervescence  and  the  escape  of  red  fumes, 

*  It  occasionally  presents  the  various  tarnishes  already  described 
as  occurring  upon  ingots. 


70  ORES  OF  COPPER. 

and  gives  a  blue  solution  with  ammonia.  By  these  pro- 
perties together  with  its  malleability,  it  is  easily  distin- 
guished from  all  other  substances. 

Native  copper  is  very  extensively  distributed  over  the 
earth's  surface,  being  a  common  mineral  in  most  copper 
mines.  Very  fine  crystals  are  obtained  from  the  Faroe 
isles  and  from  Siberia.  Cornwall  contains  considerable 
quantities  of  it,  and  the  South  American  mines  also 
furnish  it.  It  is  found  abundantly  in  the  United  States. 
In  New  Jersey  it  is  quite  common,  especially  at  Schuyler's 
mine,  Flemington,  Brunswick  and  Somerville.  Near  the 
last  named  place,  a  mass  was  found  weighing  78  pounds, 
which  is  said  originally  to  have  weighed  128  pounds. 
Near  New  Haven,  Connecticut,  a  mass  was  found  weigh- 
ing 90  pounds.  There  is  much  native  copper  in  Vir- 
ginia, along  the  Blue  Ridge,  where  it  is  commonly  found 
in  broad  sheets  of  variable  thickness,  coating  epidotic 
trap  and  filling  up  the  seams  in  that  rock.  At  Manassa's 
Gap,  in  Fauquier  county,  it  is  diffused  through  the  trap, 
in  combination  with  the  two  oxides  and  silicate  of  cop- 
per. Its  greatest  masses,  however,  occur  upon  the 
shores  of  Lake  Superior. 

The  Lake  Superior  copper  contains  also  native  silver, 
generally  occurring  in  cavities  of  the  copper.  It  is  also 
said  to  be  alloyed  with  silver  to  the  extent  of  0.3  per 
cent. ;  but  I  have  repeatedly  analyzed  specimens  of  this 
copper,  and  only  in  a  few  instances  have  I  discovered 
the  more  valuable  metal.  Specimens  there  are  undoubt- 
edly which  contain  much  more  than  that  amount,  but 
the  majority  have  only  a  trace  of  silver,  and  in  many 
fragments  none  at  all  can  be  detected.  Hautefeuille 
has  recently  detected  mercury  in  this  copper. 


ORES  OF  COPPER.  71 

CLASS    II. 

Red  Copper  may  be  massive,  granular,  earthy,  or 
crystallized.  Its  crystals  belong  to  tbe  same  system  as 
native  copper.  When  pure,  it  is  usually  of  a  fine  co- 
chineal red  color,  though  it  is  occasionally  crimson, 
especially  by  transmitted  light.  Sometimes,  however, 
the  opaque  crystals  have  an  iron-gray  tint  upon  the  sur- 
face, resulting  probably  from  oxydation ;  but  even  in 
this  case,  the  red  color  shows  itself  when  the  crystal 
is  pulverized.  The  finest  specimens  are  transparent, 
and  have  a  rich  ruby  hue. 

"When  massive,  it  is  usually  found  in  connection  with 
native  copper  and  the  black  oxide.  It  occurs  mingled 
with  metallic  copper  and  the  black  oxide,  above  and 
between  the  bricks  of  a  refining  furnace.  Many  beau- 
tiful specimens  may  be  obtained  from  such  spots,  the 
clear  ruby  red  of  this  compound  contrasting  finely  with 
the  rich  steel  gray  of  the  fused  black  oxide.  Tile  ore 
is  an  earthy  variety,  usually  brownish  or  dark  brick 
red.  It  is  mixed  with  a  variable  amount  of  red  oxide 
of  iron.  In  Cornwall,  and  at  Rheinbreitenbach,  on  the 
Rhine,  it  is  found  in  capillary  crystallizations,  to  which 
the  name  cJialclwtricJiite  has  been  given. 

This  oxide  is  found  in  many  mines,  the  finest  crys- 
tals being  obtained  from  Chessy,  Moldawa,  and  Eka- 
therinenburg.  Cornwall,  especially  at  Huel  Garland 
mine,  near  Redruth,  furnishes  octahedral  crystals.  In 
this  country,  it  has  been  found,  in  the  New  Jersey 
mines,  in  the  Tennessee  and  Virginia  mines,  and  at 
Manassa's  Gap,  in  Virginia. 


72  ORES  OF  COPPER. 

The  composition  of  this  ore,  according  to  an  analysis  of 
Chenevix,  is : 

Copper,       -  -  88.78 

Oxygen,      -  11.22 

Its  formula  is  Cu20,  and  its  specific  gravity  5.992. 

Before  the  blowpipe,  in  the  reducing  flame  on  char- 
coal, it  affords  a  globule  of  copper.  It  dissolves  in  hot 
muriatic  acid,  excluded  from  the  air,  forming  a  colorless 
solution,  which  gradually  becomes  green  when  exposed 
to  the  atmosphere.  In  nitric  acid  it  dissolves  with  effer- 
vescence, forming  a  blue  solution.  From  its  hydrochloric 
solution,  water  throws  down  a  white,  and  potash  a  yel- 
low precipitate. 

Black  Oxide  of  Copper  is  commonly  found  in  powder 
or  friable  masses,  of  an  earthy  appearance,  mixed  with 
sulphurets,  arseniarets,  &c.,  resulting  from  atmospheric 
action  upon  the  other  ores  of  the  vein.  It  is  occasion- 
ally found  massive,  containing  crystals  of  cubic  or  allied 
forms.  Its  lustre  may  be  submetallic  and  earthy,  or 
metallic  and  bright.  Beautiful  steel  gray  specimens  may 
be  obtained  from  the  hearth  of  an  old  refining  furnace. 

Tenorite  is  a  variety  found  in  the  lava  of  Vesuvius, 
in  small  scales,  hexagonal  or  triangular  in  form,  of  a 
dark  steel-gray  hue  by  reflected,  and  brown  by  trans- 
mitted light. 

The  black  oxide  is  found  coating  many  different  ores, 
and  is  a  product  of  most  mines.  In  Polk  county,  Ten- 
nessee, however,  it  exists  in  great  quantities,  beds  of  it, 
from  25  to  90  feet  in  thickness,  being  worked  there. 
At  Keweenaw  Point,  Lake  Superior,  the  compact  vari- 
ety has  been  found,  and  at  Manassa's  Gap,  in  Virginia, 


ORES  OP  COPPER.  73 

it  occurs  massive,  mixed  with  native  copper,  red  oxide, 
and  chrysocolla, 

Its  composition  is : 

Copper,       -  79.86 

Oxygen,      -  20.13 

Its  formula  is  CuO,  or  Cu.  Its  specific  gravity  va- 
ries, of  course,  with  its  state  of  aggregation.  That  of 
Keweenaw  Point,  is  stated,  by  Dana,  on  the  authority  of 
a  private  communication  from  Teschemacher  and  Hayes, 
to  be  5.140  for  the  crystals,  and  5.386  for  the  compact 
portions. 

It  dissolves  with  a  green  color  in  muriatic  acid, 
and  without  effervescence  in  nitric  acid.  Its  blowpipe 
reactions  are  the  same  as  those  of  the  last  variety. 

Atacamite  is  a  beautiful  emerald,  or  blackish  green 
mineral,  found  in  Chili  and  Bolivia.  Its  system  of 
crystallization  is  trimetric,  and  it  usually  occurs  in  rec- 
tangular prisms  or  rectangular  octahedra.  It  is  also 
found  massive. 

It  was  originally  found,  in  the  state  of  sand,  in  the 
desert  of  Atacama,  between  Chili  and  Peru,  whence  its 
name.  It  also  occurs'  at  Los  Remolinos,  in  Chili,  at 
Cobija,  in  Bolivia,  and  coating  the  lavas  of  Vesuvius 
and  Etna. 

Its  composition  varies  according  to  different  observers. 
We  give  two  per  centage  statements: 

Chloride  of  Copper,  -  31.48  27.94 
Oxide  of  Copper,  -  55.94  49.57 
Water,  -  -  12.58  22.49 


100.00    100.00 


74  ORES  OF  COPPER. 

Its  formula,  therefore,  is  CuCl+3CuO+3HO,  or 
CuCl+3CuO+6HO. 

It  tinges  the  blowpipe  flame  green  or  blue,  and  gives 
off  fumes  of  hydrochloric  acid  ;  and,  on  charcoal,  yields 
a  bead  of  metallic  copper.  It  is  soluble  in  acids. 

CLASS   III. 

Copper  Grlance,  or  Vitreous  Copper,  called  also  Sul- 
phuret  of  Copper,  is  of  an  iron  gray  or  blackish  lead- 
gray  color,  often  tarnished  with  blue  or  green,  and 
sometimes  iridescent.  Its  crystals  belong  to  the  tri- 
metric  system.  The  primitive  form  is  a  six-sided  prism, 
but  it  is  commonly  found  in  hexagonal  tables.  It  is 
more  frequently  met  with  massive.  It  is  very  soft  and 
friable,  may  be  readily  cut  with  a  knife,  and  when 
scratched,  gives  a  shining  streak  the  color  of  the  ore. 
It  is  very  fusible,  melting  in  the  flame  of  an  ordinary 
candle. 

Fine  crystals  of  this  species  are  found  in  Cornwall, 
especially  in  the  neighborhood  of  Redruth,  whence  one 
of  its  names,  Redruthite.  It  occurs  massive,  in  nume- 
rous localities,  both  in  Europe  and  the  United  States. 
Crystals,  of  fine  size  and  great  brilliancy,  have  been 
found  at  the  Bristol  mine,  in  Connecticut. 

The  composition  of  this  mineral,  when  pure,  is : 
Copper,  79.8 

Sulphur,  20.2 

100 
Usually,  however,  it  is  contaminated  with  iron,  which 


ORES  OF  COPPER. 


75 


makes  it  harder  and  more  infusible.     Thompson's  analy- 
sis of  a  Cornish  specimen  is  as  follows : 

Copper,         -  77.16 

Sulphur,       -  20.62 

Iron,  1.15 

98.93 

It  is,  therefore,  a  sulphuret  of  copper,  its  formula 
being  CuS.  Its  specific  gravity  varies  from  5.5  to  5.8. 

Before  the  blowpipe,  in  the  outer  flame,  "  it  melts, 
gives  oif  fumes  of  sulphur,  and  emits  glowing  drops  with 
a  noise,  coloring  the  flame  at  the  same  time  blue.  In 
the  inner  flame,  it  becomes  covered  with  a  coating,  and 
does  not  melt."  The  blue  tinge  of  the  flame  is  espe- 
cially observed,  if  the  specimen  has  previously  been 
moistened  with  hydrochloric  acid.  On  charcoal,  it  gives 
off  fumes  of  sulphurous  acid,  and  leaves  a  bead  of  cop- 
per. In  nitric  acid  it  dissolves  to  a  green  solution,  floc- 
culi  of  sulphur  floating  through  the  liquid. 

Harrisite,  This  has  been  described  by  Prof.  C.  H. 
Shepard  as  a  new  mineral  species.  It  is  regarded  by 
Genth  as  a  pseudomorph  of  copper-glace  after  galena. 
It  occurs  at  the  Canton  mine,  Cherokee  county,  Geor- 
gia, in  forms  closely  resembling  those  of  galena.  My 
specimens  are  of  a  dark  iron-gray,  with  perfect  cubical 
cleavage  down  to  the  smallest  fragment.  Some  of 
them  have  the  foliated  character  of  which  Dr.  Genth 
speaks,  and  most  of  them  are  curved  as  though  they 
had  been  bent  after  they  had  been  deposited. 

The  following  are  the  results  of  two  determinations 
by  Dr.  Genth : 


76  ORES  OF  COPPER. 

Sulphur,  20.648  20.647 

Selenium,  not  determined  0.047 

Silver,  0.207  0.164 

Copper,  77.298*  77.758 

Lead,  0.056  0.060 

Iron,  0.442  0.359 

Insoluble,  -               0.272  0.667 


98.923        99.702 

Sp.  gr.  5.485.     H.  3  to  3.5. 

Digenite  is  an  allied  mineral,  found  in  Chili,  and  at 
Saugenhausen,  in  Thuringia.  Its  specific  gravity  is 
4.6.  It  is  supposed  to  be  a  mixture  of  copper  glance 
and  covelline. 

Berzelianite  is  a  selenide  of  copper,  occurring  in  thin 
dendritic  crusts,  of  a  silver-white  color  and  a  metallic 
lustre.  It  is  found  in  Sweden  and  the  Hartz  mountains, 
and  is  of  no  value  as  an  ore. 

Covelline,  or  Indigo  Copper,  is  found  in  crystals  be- 
longing to  the  hexagonal  system,  and  also  massive  or 
spheroidal,  with  a  crystalline  surface.  Its  color  is 
indigo  blue,  its  lustre  resinous,  its  streak  lead-gray  and 
shining.  Before  the  blowpipe  it  burns  with  a  blue 
flame  before  becoming  red  hot,  and  fuses  to  a  globule, 
which  is  strongly  agitated  and  emits  sparks,  finally 
yielding  a  button  of  copper.  Its  composition  is  Copper 
66.5,  Sulphur  33.5. 

Cantonite.  A  pseudomorph  of  Covelline  has  been 
described  under  this  title  by  N.  A.  Pratt,  Jr.  He  says 

*  Some  accidentally  lost. 


ORES  OF  COPPER.  77 

it  is  found  finely  crystallized  in  well-formed  cubes,  of 
submetallic  lustre  and  blue-black  color,  and  gives  its 
specific  gravity  as  4.18,  and  its  hardness  as  1.5  to  2. 
His  analysis  (No.  I.)  may  be  compared  with  Dr.  Genth's 
(No.  II.) 

i.  11. 

Sulphur,  33.490         32.765 

Copper,  66.205         65.604 

Selenium,  ^j       -  trace 

Silver,  0.355 

Lead,  .305          0.107 

Iron,  0.251 

Insoluble,  J      -  0.157 


100.00        99.239 

Genth  calls  it  a  pseudomorph  of  Covelline,  after  Ga- 
lena. 

JEnibescite,  Phillipsite,  Variegated  Copper,  or  Purple 
Copper,  belongs  to  the  monometric  system  of  crystalli- 
zation. Its  crystals  are  ill-defined,  and  usually  cubes 
or  octahedra.  Most  frequently  it  occurs  granular  or 
compact.  Its  lustre  is  metallic,  its  color,  in  fresh  frac- 
tures, reddish-brown,  something  between  copper  and 
pinchbeck,  and  it  is  commonly  tarnished  with  different 
hues  of  blue,  purple,  and  red.  It  is  brittle,  and  breaks 
with  an  uneven,  small  conchoidal  fracture. 

It  is  an  important  ore  of  copper,  being  found  in  Corn- 
wall, Killarney,  Tuscany,  Mansfield,  Norway,  Silesia, 
Siberia,  and  the  Bannat.  It  also  occurs  in  Pennsylva- 
nia, Massachusetts,  Connecticut,  and  New  Jersey,  and 
in  most  of  the  mining  districts  of  South  America. 
7* 


78  ORES  OF  COPPER. 

Its  composition  is : 

Berzelius.  Kammelsberg. 

Copper,     -  62.5  55.5 

Iron,  13.8  16.4 

Sulphur,    -  -  33.7  28.1 


100.0         100.0 

Analysis  of  different  specimens  differ  still  more 
widely  than  these  two  statements,  the  copper  ranging 
from  71  to  56  per  cent.  This  may  be  accounted  for 
by  supposing  it  to  be  variously  mixed  with  other  ores  of 
copper.  The  only  two  analyses  of  crystals  approach 
much  nearer  Rammelsberg's  than  Berzelius'  table.  Its 
formula,  according  to  Berzelius,  is  2Cu2S+FeS,  and 
according  to  Rammelsberg,  3Cu2S+Fi2S3. 

Before  the  blowpipe  it  blackens  and  becomes  red  on 
cooling,  or  if  sufficiently  heated,  fuses  to  a  black  glo- 
bule, which  is  attracted  by  the  magnet. 

Barnhardite  is  a  new  mineral,  described  by  Dr. 
Genth,  of  Philadelphia.  It  occurs  in  compact  masses. 
Specific  gravity,  4.521 ;  lustre  metallic,  but  somewhat 
dull ;  color  bronze-yellow ;  streak  grayish  black  and 
slightly  shining ;  opaque  ;  fracture  conchoidal,  uneven ; 
tarnishes  very  soon — more  readily  in  presence  of  mois- 
ture, assuming  a  peculiar  brownish,  sometimes  pinch- 
beck-brown ;  sometimes,  also,  rose-red  and  purple  color. 

Before  the  blowpipe,  gives  off  sulphurous  acid,  and 
fuses  easily  to  an  iron-black  magnetic  globule  ;  and  with 
borax,  it  gives  the  relations  of  copper  and  iron ;  with 
carbonate  of  soda  and  borax,  metallic  copper.  The 
calculated  composition  is  as  follows  : 


ORES  OF  COPPER.  79 

Copper,       -  48.14 

Iron,  21.33 

Sulphur,      -  30.53 

The  formula  is  2Cu2S+Fe2S3. 

"I  have  found  this  mineral  associated  with  other 
copper  ores  at  Dan.  Earnhardt's  land,  (hence  its  name,) 
and  Pioneer  Mills,  Cabarrus  county ;  Dr.  0.  Dieffen- 
bach  observed  it  in  the  Phcenix  and  -Vanderburg  mines 
of  the  same  county,  and  I  saw  it  also  amongst  copper 
ores  from  the  neighborhood  of  Charlotte,  Mecklenberg 
county,  N.  C.  It  seems  to  be  abundant  in  North  Caro- 
lina, and  is,  of  course,  a  very  valuable  copper  ore."* 

Copper  Pyrites  is  a  yellow  ore,  with  a  brilliant  metal- 
lic lustre,  and  is  often  mistaken  by  the  inexperienced  for 
native  gold.  It  usually  occurs  massive,  having  an 
irregular  and  slightly  conchoidal  fracture.  It  is  also 
found  botryoidal,  globular,  stalactitic,  and  crystallized. 
Its  crystals  are  octahedral  or  tetrahedral,  and  belong 
to  the  dimetric  system.  It  is  liable  to  tarnish,  and  is 
sometimes  iridescent.  Its  streak  is  greenish  black  and 
shining,  and  its  powder  is  a  fine  bronze  green. 

This  is  the  most  abundant  of  all  the  ores  of  copper. 
It  is  the  principal  product  of  the  Cornish  mines,  which 
yielded,  in  1853,  180,000  tons  of  ore.  It  is  also  worked 
in  Scotland,  Sweden,  Germany,  Hungary,  Australia. 
In  the  United  States,  it  is  a  very  frequent  accompani- 
ment of  galena,  and  is  also  found  alone  in  numerous 
places.  It  is  worked  in  several  of  the  States,  but  its 
localities  will  be  described  in  the  chapter  on  Mines. 

--  American  Journal  of  Science  and  Art,  January,  1855,  p.  18. 


80  OHES  OF  COPPER. 

Its  composition  is  : — 

Copper  34.47 

Iron  30.48 

Sulphur        -  35.05 


100.00 

Its  formula  is  Cu2S-f  Fe2S3.  Its  specific  gravity  varies 
from  4.1  to  4.3. 

Before  the  blowpipe,  at  a  low  heat  it  blackens,  but 
becomes  red  on  cooling,  in  consequence  of  the  oxidation 
of  its  iron.  At  a  higher  heat,  it  fuses  to  a  black,  brittle 
globule,  which  is  attracted  by  the  magnet,  and  if  the 
heat  be  kept  up  long  enough,  upon  charcoal,  it  yields  a 
metallic  globule.  Fused  with  a  small  quantity  of  borax, 
it  also  furnishes  a  bead  of  pure  copper.  Nitric  acid 
forms  with  it  a  green  solution,  having  sulphur  in  the 
liquid. 

This  ore  need  not  be  mistaken  for  anything  else.  It 
is  easily  distinguished  from  gold  by  the  fact  that  it  is 
not  malleable.  From  iron  pyrites  it  may  be  distinguished 
by  its  color,  which  is  a  rich  golden  yellow,  while  that  is 
a  pale  brass-color,  and  also  by  its  softness,  iron  pyrites 
being  hard  enough  to  strike  fire  with  steel.  It  is,  how- 
ever, often  intermixed  with  this  other  mineral,  and  then 
it  is  both  paler  and  harder  than  the  pure  variety.  The 
action  of  nitric  acid  is  also  characteristic. 

The  copper  pyrites  of  commerce  is  a  very  variable 
ore,  and  it  is  not  always  easy  for  the  most  experienced 
to  determine  its  value  by  simple  inspection.  It  is  com- 
monly largely  mixed  with  silicate  of  copper,  malachite, 
iron  pyrites  and  quartz,  and  some  of  the  poorest  ores, 


ORKS  Oi1  COPPER.  81 

when  pounded  up  and  dressed,  can  hardly  be  distinguish- 
ed from  the  best.  There  is  a  very  deceptive  ore  of  this 
kind  in  Louisa  county,  Virginia.  It  is  essentially  an 
iron-pyrites  with  sufficient  copper  diffused  through  it, 
to  give  it  the  black  tarnish  common  on  the  rich  Cuba 
ores,  and  yet  samples  of  it,  when  dressed  and  sent  to 
market,  though  looking  very  well,  have  furnished  only 
between  from  one  and  two  per  cent,  of  copper.  *  , 

Domeylcite,  or  arsenical  copper  is  a  tin-white,  slightly 
yellowish  mineral,  often  presenting  an  iridescent  tarnish, 
occurring  in  reniform  and  botryoidal  inasses,  as  well  as 
massive  and  disseminated.  It  is  found  in  Chili  and 
in  Cornwall.  It  is  composed  of  arsenic  28.3,  copper 
71. 7.  Before  the  blowpipe  it  fuses,  giving  off  the  gar- 
licky color  of  arsenic. 

Oondurrite,  a-  mixture  of  domeykite,  with  red  copper 
ore  and  arsenite  and  sulphuret  of  copper,  is  greenish- 
black  or  blue  in  color,  and  soft  in  texture. 

G-ray  copper,  fahlerz  of  the  Germans,  usually  occurs 
massive,  but  is  also  found  in  cubes  and  tetrahedra, 
belonging  to  the  monometric  system.  Its  color  varies 
from  steel-gray  to  iron-black,  and  its  streak  is  the  same 
color  or  slightly  brownish.  It  is  brittle  and  has  a  con- 
choidal  fracture. 

In  composition  it  is  a  very  variable  mineral,  as  the 
following  table  will  show  : — 

*  Breithaupt  describes  a  variety  of  this  pyrites  under  the  name  of 
Cuban,  occurring  in  cubes  or  massive.  Its  color  is  between  bronze 
and  brass-yellow,  its  streak  black,  its  hardness  4 ;  its  specific  gravity, 
4.026.  It  contains  19  per  cent,  of  copper,  fuses  easily  before  the  blow- 
pipe, giving  off  fumes  of  sulphur  but  no  arsenic.  His  specimens  came 
from  the  Island  of  Cuba.  I  have  seen  it  occasionally  in  cargos  of  ore 
from  the  West  coast  of  South  America. 


ORES  OF  COPPER. 


s 
m  Clausthal, 

Iphur.  Antimony 
24.73      28.34 

Arsenic 

Copper 
34.48 

Iron.  Zinc.  Silver.  Gold.  Quartz. 
2.27  5.55    4.97      "        "    Rose. 

'    Wolfacli, 

23.52 

26.63 

" 

25.33 

3.72  3.10  17.71      " 

"   Rose. 

'    Corbiers, 

25.30 

25.00 

1.50 

34.30 

1.70  6.30 

0.70      " 

"    Berthier. 

'    Gersdorf, 

26.33 

16.52 

7.21 

38.63 

4.89  2.76 

237      " 

"    Rose. 

'    Unknown, 

10.00 

" 

14.00 

48.00  25.50    " 

0.50      " 

"    Klaproth. 

'  Cabflrrus  ) 

25,48 

17.76 

11.55 

30.73 

1.42  2.53 

10.53      " 

"   Genth. 

Co.  N.C.    ) 

"  Bucking-  ) 

28.46 

5.10 

16.99 

40.64 

4.24  3.39 

0.42  Tract 

1.24  Taylor. 

From  this  table,  it  would  appear  impossible  to  con- 
struct anything  like  a  formula  for  this  mineral.  It  is 
usually  said  to  be  4(Ag,Cu2ZnFe)S  and  (As,Sb)S3, 
— but  it  is  manifest  that  neither  this  nor  any  other 
can  apply.  Dr.  Gentli  considers  his  specimen  from 
Cabarrus  county  a  new  species,  and  offers  for  it  the 
formula  5(Ag,Cu2,Zn,Fe)Sx2(As,Sb)S3.  Rose  thinks 
that  the  general  composition  of  the  mineral  may  be 
represented  by  the  formula  Fe4Cu16Sb6S21,  in  which  each 
of  the  different  metallic  substances  may  be,  to  a  greater 
or  less  extent,  replaced  by  others,  so  that  sulphuret  of 
antimony  may  be  substituted  by  sulphuret  of  arsenic, 
and  sulphuret  of  copper  by  sulphuret  of  silver. 

The  blowpipe  reactions  must  necessarily  vary  some- 
what. They  usually,  however,  consist  in  the  evolution 
of  fumes  of  antimony  and  arsenic,  the  former  recognized 
by  its  white  smoke,  and  the  latter  by  its  garlicky  odor. 
With  this  is  combined  the  odor  of  sulphuric  acid  from 
the  sulphur  present.  The  coal  will  be  covered  with  the 
white  incrustation  of  antimony,  or  if  zinc  be  present  by 
a  yellow  sublimate,  becoming  snow-white  on  cooling. 
"When  finely  powdered,  it  dissolves  in  nitric  acid,  leaving 
a  slight  residue,  and  forming  a  brownish-green  solution. 

Dr.  Genth  gives  the  following  as  the  re-actions  of  his 
Cabarrus  county  ore.  "Before  the  blowpipe,  decrepi- 
tates slightly ;  in  an  open  tube  disengages  sulphurous 


ORES  OP  (JOPPER.  83 

acid,  gives  a  sublimate  of  arsenious  acid ;  on  charcoal  it 
emits  fumes  of  an  alliaceous  odor  and  covers  it  with 
white  incrustations  ;  it  fuses  into  a  magnetic  globule  and 
gives  with  fluxes  the  re-actions  of  copper  and  iron." 

This  is  a  very  important  ore  of  copper,  and  is  additi- 
tionally  valuable  from  the  silver  it  contains.  It  occurs 
in  fine  crystals  near  Cornwall,  near  St.  Austell,  though 
their  surface  is  commonly  rough  and  dull.  More  bril- 
liant crystallizations  are  found  at  St.  Andreasberg  in  the 
Hartz  ;  Kremnitz,  in  Hungary ;  Freyberg,  in  Saxony ; 
Dillenberg,  in  Warsaw ;  and  Kapnik,  in  Transylvania. 
It  is  found  massive  in  the  Tyrol,  and  in  Siberia.  In  the 
United  States,  according  to  Dr.  Genth  who  first  discov- 
ered it  in  this  country,  it  occurs  in  Cabarrus  county, 
North  Carolina  ;  at  Eldridge's  gold  mine  in  Buckingham 
county,  Virginia ;  and  in  Duchess  county,  New  York. 

Tennantite  has  a  close  resemblance  to  gray  copper, 
and  occurs  in  brilliant  crystals  investing  other  ores  of 
of  copper.  It  is  found  in  Cornwall  and  Norway. 

Wolfsbergite,  or  antimonial  copper,  is  a  sulphantimcr- 
niate  of  copper,  occurring  in  small  aggregated  tabular 
prisms,  in  quartz,  at  Wolfsberg  in  the  Hartz. 

Bournonite  is  a  gray  or  blackish  mineral,  crystallizing 
in  prisms,  belonging  to  the  trimetric  system.  Its  lustre 
is  metallic,  its  fracture  conchoidal  and  uneven. 

Rose's  analysis  of  a  specimen  from  Pfafienberg,  is : — 
Copper,  ir*»        12.65 

Lead  ifsi:       40.84 

Antimony        -  -         26.28 

Sulphur          -          ri^fr    in*       20.31 


100.08 


84  ORES  OF  COPPER. 

Before  the  blowpipe,  it  fuses  to  a  black  globule,  and 
gives  off  fumes  of  antimony.  At  a  high  heat  the  charcoal 
is  coated  with  a  yellow  deposit  of  oxide  of  lead.  It  dis- 
solves easily  in  nitric  acid,  forming  a  blue  solution. 

It  is  found  in  several  of  the  European  mines,  but  has 
not  yet  been  discovered  in  this  country. 

CLASS  IV. 

Dioptase  is  a  rare  and  beautiful  emerald  green,  trans- 
parent or  translucent  mineral,  occurring  in  rhombohedral 
crystals,  in  quartz,  at  Altyn  Tube*,  in  Siberia.  Its  lustre 
is  various,  its  streak  green,  and  its  fracture  conchoidal 
and  uneven.  It  is  a  silicate  of  copper,  containing  3 
equivalents  of  oxide  of  copper,  2  of  silicic  acid,  and  3  of 
water. 

Chrysocolla  is  a  silicate  of  copper,  occurring  usually 
as  an  incrustation,  but  sometimes  disseminated  through 
quartz.  It  has  various  tints  of  blue  and  green,  from  a 
turquoise  color  to  a  bright  mountain-green.  It  is  some- 
times brown  from  admixture  of  foreign  ingredients,  espe- 
cially iron.  The  translucent  varieties  are  hard  and  brit- 
tle, the  opaque  ores  soft  and  earthy.  It  is  often  mixed 
with  other  ores,  especially  with  the  carbonates  of  cop- 
per. 

It  is  a  very  common  ore  of  copper,  and  attends  almost 
every  deposit  of  that  metal  which  has  a  silicious  vein- 
stone. It  is  in  primitive  regions,  especially  in  granite, 
a  frequent  surface  indication,  being  often  diffused  through 
the  quartz  rocks,  so  as  to  give  them  a  decided  green 
stain.  At  Manassa's  Gap,  it  envelops  the  native  copper 
and  the  oxides  of  copper  which  are  diffused  through  the 
quartz. 


ORES  OF  COPEER.  85 

Its  composition  is  : — 

Silica  *$*,        34.82 

Oxide  of  copper  •*:-       44.83 

Water  -         20.35 

Its  formula  is  3CuO,2Si03+6HO.  Its  specific  gravity 
is  from  2  to  2.238.  Before  the  blowpipe,  on  charcoal, 
it  blackens  in  the  inner  flame  but  does  not  melt.  With 
borax,  it  fuses  to  a  green  glassy  globule,  containing  some 
specks  of  metallic  copper. 

CLASS  v. 

Azurite  occurs  in  beautiful  azure  blue  crystals,  belong- 
ing to  the  monoclinic  or  rhomboidal  system.  These  are 
transparent  or  subtranslucent,  having  a  glassy  or  ada- 
mantine lustre,  and  a  conchoidal  fracture.  The  streak 
is  a  lighter  blue.  It  also  is  found  in  mamillary  concre- 
tions, and  in  dull  earthy  masses. 

The  finest  crystals  come  from  Chessy,  near  Lyons ; 
though  excellent  specimens  are  found  in  the  Bannat,  in 
Siberia,  and  in  Cornwall.  In  this  country  it  is  found 
at  Perkiomen,  near  Philadelphia,  and  at  other  places 
in  Pennsylvania.  It  is  also  to  be  obtained  near  Sing 
Sing,  in  New  York,  and  near  New  Brunswick,  in  New 
Jersey. 

Its  composition  is 

Oxide  of  copper  .^        69.09 

Carbonic  acid  ....-  j,        -         25.69 

Water  5.22 

100.00 


86  ORES  OF  COPPER. 

Its  formula  is  2CuO,C02+CuO,HO;  its  specific  grav- 
ity 3.5  to  3.831.  Before  the  blowpipe,  in  the  oxidating 
flame,  it  is  reduced  to  a  black  globule.  In  the 
reducing  flame  in  the  loop,  it  burns  with  a  green  flame, 
and  on  charcoal  is  reduced  to  metal.  Heated  in  a  glass 
tube,  it  gives  off"  water  and  becomes  black.  Fused  with 
borax,  it  forms  a  green  glass.  It  dissolves  in  ammonia 
and  the  acids,  effervescing  with  the  latter. 

It  has  been  ground  to  a  powder  and  used  for  paint, 
but  is  liable  to  turn  green. 

Malachite  is  a  mineral  of  various  shades  of  green, 
mostly  emerald.  It  is  found  in  crystals  belonging  to  the 
monoclinic  system,  but  more  commonly  occurs  in  botryoi- 
dal  masses,  which  are  often  radiated,  and  sometimes 
made  up  of  minute  crystals.  Occasionally  they  seem  to 
have  been  formed  in  successive  layers,  the  boundaries  of 
which  are  distinctly  seen  on  breaking  the  mass.  I  have 
some  specimens  from  Patapsco  mine,  in  Carrol  county, 
Maryland,  which  form  beautiful  green  fibrous  cones,  an 
inch  or  more  in  height,  imbedded  in  a  soft,  red,  ferru- 
ginous mass.  It  is  also  found  in  a  friable  and  pulveru- 
lent state,  when  it  is  commonly  mixed  with  various 
earthy  impurities. 

It  is  met  with  in  great  masses  in  Siberia,  and  it  has 
been  wrought  into  table-tops,  &c.  The  Emperor  of  Rus- 
sia, some  years  since,  presented  the  King  of  Prussia 
with  a  pair  of  beautiful  vases,  of  great  size,  made  of  this 
material.  It  is  valuable  not  only  as  an  ore  of  copper, 
but  also  as  a  precious  stone,  being  wrought  by  the  lapi- 
dary into  numerous  articles  of  jewelry.  It  is  a  very 
convenient  form  for  the  manufacture  of  blue  vitriol,  and 


ORES  OF  COPPER.  87 

is  also  ground  into  a  paint  for  the  use  of  artists.     In 

smaller   quantities,  it  is  an  accompaniment  of  almost 
every  ore  of  copper. 
It  composition  is 

Oxide  of  copper  -         71.82 

Carbonic  acid  -         20.00 

Water             -  -            -           8.18 


100.00 

Its  formula  is  2CuO,C02+HO.  Its  reactions  are 
the  same  as  those  of  azurite.  Its  specific  gravity  is 
from  3.7  to  4.008.  It  is  often  mixed  with  lime,  zinc, 
and  other  substances,  and  these  mixtures  have  occasi- 
onally been  described  as  distinct  minerals. 

Blue  vitriol  has  already  been  sufficiently  described  in 
the  previous  chapter.  It  is  found  at  most  mines  of  the 
sulphurets  of  copper,  as  a  consequence  of  the  oxidation  of 
these  ores,  and  the  subsequent  solution  and  crystalliza- 
tion of  the  resulting  salt  of  copper.  It  is  of  course 
impure  from  the  presence  of  iron.  At  some  mines,  the 
blue  water  running  from  the  ore  is  collected  in  cisterns, 
into  which  scrap-iron  is  thrown.  This  precipitates  the 
copper  which  is  slowly  oxidated,  so  that  a  mixture  of  red 
oxide  and  metallic  copper  is  the  result,  a  compound 
easily  and  cheaply  reduced  to  the  metallic  state.  • 

BrocJiantite  is  a  mixture  of  sulphate  of  copper  and 
the  hydrated  oxide,  in  the  proportion  of  one  of  the  former 
to  three  of  the  latter.  Its  lustre  is  vitreous,  its  color 
emerald-green  or  blackish-green,  its  streak  is  paler.  It 
occurs  in  transparent  crystals,  belonging  to  the  trimetric 
system,  also  in  masses  and  botryoidal  concretions. 


88  ORES  OF  COPPER. 

Lettsomite  is  a  velvety  blue  coating  on  an  earthy 
hydrated  oxide  of  iron,  occurring  sparingly  at  Moldawa 
in  the  Bannat.  It  is  a  mixture  of  the  sulphates  of 
copper  and  alumina,  the  oxide  of  copper  and  water. 

Oonnellite  is  a  blue,  translucent  mineral,  with  a  vitre- 
ous lustre,  occurring  in  hexagonal  prisms  in  Cornwall. 
It  is  a  mixture  of  the  sulphate  and  the  chloride  of 
copper. 

Thrombolite  is  an  amorphous,  green,  opaque  phos- 
phate of  copper,  with  a  vitreous  lustre,  found  at  Retz- 
banya,  in  Hungary. 

Before  the  blowpipe,  it  colors  the  flame  first  blue  and 
then  green.  On  charcoal  it  fuses  easily  to  a  black 
globule,  and  then  yields  a  bead  of  copper. 

Phosphorochalcite  is  a  dark  green,  translucent  phos- 
phate of  copper,  found  at  Rheinbreitenbach,  Nischne 
Tagilsk  and  Hirschberg. 

Libethenite  is  an  olive-green,  subtranslucent  phosphate 
of  copper,  having  a  resinous  lustre  and  a  subconchoidal 
fracture.  It  belongs  to  the  trimetric  system  of  crys- 
tallization. It  is  found  in  Hungary,  Cornwall  and  the 
Ural  Mountains. 

Olivenite  is  a  phosphate  and  arseniate  of  copper,  of  a 
dark  green  or  brown  color,  crystallizing  in  forms  belong- 
ing to  the  trimetric  system,  and  also  occurring  in  globu- 
lar, reniform  and  fibrous  concretions. 

Euchroite  is  a  bright  emerald  or  leek-green  mineral, 
found  at  Libethen,  in  Hungary,  in  large  crystals.  It 
contains  33  per  cent,  of  arsenic  acid,  and  54  of  oxide  of 
copper. 

Tyrolite  is  a  pale  green  mineral,  composed  of  arse- 


OKES  OF  COPPER.  89 

niate  of  copper,  carbonate  of  lime  and  water.  It  occurs 
in  the  cavities  of  calamine,  calc-spar  or  quartz,  accom- 
panied by  other  ores  of  copper,  appearing  in  small  ag- 
gregated and  diverging  fibrous  groups,  possessing  a 
delicate  silky  lustre. 

Erinite  occurs  in  mamillated,  crystalline,  roughened 
coatings,  made  up  of  several  layers  often  easily  separa- 
ble. Its  color  is  a  fine  emerald-green,  inclining  to  grass- 
green,  its  streak  paler.  It  contains  33.78  per  cent,  of 
arsenic  acid,  59.44  of  oxide  of  copper,  5.01  of  water, 
and  1.7T  of  alumina.  It  is  found  in  the  county  of 
Limerick,  in  Ireland. 

Aphanesite  is  of  a  dark  green  color,  inclining  to  blue, 
and  sometimes  to  dark  blue.  Its  crystals  are  brilliant, 
but  small,  and  belong  to  the  monoclinic  system.  It  is 
found  in  Cornwall  and  in  the  Erzgebrige,  and  contains 
30  per  cent,  of  arsenic  acid  and  54  of  oxide  of  copper. 


CHAPTER  III. 

ANALYSIS   OF    COPPER   ORES. 

IN  the  first  chapter  we  have  given  an  account  of  the 
reactions  of  pure  copper.  It  is  only  necessary  to  bear 
these  in  mind,  to  be  able  to  recognize  this  metal.  Still, 
as  there  are  some  precautions  to  be  observed  in  getting 
the  solutions  to  be  operated  upon,  it  may  be  well  to  give 
here  a  brief  account  of  the  method  of  proceeding  in  the 
qualitative  examination  of  a  mineral  supposed  to  con- 
tain copper,  before  undertaking  to  describe  the  quantita- 
tive analysis  of  such  ores. 

This  will  vary  very  much  with  the  nature  of  the 
metals  which  may  happen  to  be  combined  with  the 
copper.  If,  for  example,  the  presence  of  lead  be  sus- 
pected, the  ore  must  be  treated  with  dilute  nitric  acid. 
It  is  best  to  take  a  mixture  of  one  part  of  acid  with  five 
or  six  of  water,  and  allow  it  to  stand  on  the  ore  at  a 
gentle  heat,  until  the  flakes  of  sulphur  which  havejiepa- 
rated  are  of  a  clear  yellow  color.  Should  there  be  any 
other  insoluble  matter  left,  the  solution  must  be  poured 
off,  the  residue  well  washed,  and  then  treated  with  boil- 
ing concentrated  nitric  acid,  until  nothing  is  left  un- 
dissolved  but  the  vein-stone  and  the  floating  sulphur. 
The  two  solutions  are  now  mixed,  and  to  them  is  added 
a  little  sulphuric  acid.  A  white  precipitate  immediately 
falls,  which  is  indicative  of  the  presence  of  lead. 

It  must,  however,  be  borne  in  mind  that  lime  also 


ANALYSIS  OF  COPPER   ORES.  91 

produces  a  white  precipitate  with  sulphuric  acid,  and  the 
tyro  may  be  easily  deceived.  He  will,  therefore,  remark 
that  the  lead  salt  is  the  heavier  of  the  two,  that  it  dis- 
solves readily  in  boiling  muriatic  acid,  and  that  the 
solution  on  cooling,  deposits  crystals.  A  more  decided 
distinction  is  the  action  of  sulphureted  hydrogen  or 
sulphide  of  ammonium.  The  white  precipitate  must  be 
thoroughly  washed  upon  a  filter,  and  then  subjected  to  a 
stream  of  sulphureted  hydrogen  gas,  or  moistened  with 
a  solution  of  sulphide  of  ammonium.  A  dark  brownish 
black  color  is  produced  if  the  salt  be  one  of  lead, 
whereas,  sulphate  of  lime,  when  pure,  is  unaffected  by 
either  of  these  tests.  Thorough  washing  is  essential, 
because  other  metals,  soluble  in  nitric  acid,  are  black- 
ened by  these  reagents. 

If  the  copper  ore,  under  examination,  should  be  sup- 
posed to  contain  silver,  that  question  is  determined  by 
dissolving  the  ore  in  nitric  acid,  filtering,  and  to  the 
clear  solution  adding  muriatic  acid  or  a  solution  of  salt. 
Immediately  a  white  curdy  precipitate  falls,  or  if  the 
quantity  of  silver  be  small,  a  milkiness  shows  itself  in 
the  liquid.  This  precipitate  also  needs  to  be  closely 
scanned,  for  lead  is  precipitated  by  hydrochloric  acid. 
The  lead  salt,  however,  is  heavier,  subsides  more  rapidly, 
and  is  crystalline  in  its  texture.  It  may  also  be  dis- 
solved in  a  large  quantity  of  hot  water,  and  crystallizes 
out  of  this  solution  on  cooling.  The  silver  salt,  on  the 
other  hand,  is  curdy,  subsides  slowly,  and  is  not  soluble 
in  hot  water.  It  turns  purple  or  dove-color  on  exposure 
to  light,  and  dissolves  readily  in  ammonia,  whereas  the 
lead  salt  is  insoluble  in  that  reagent,  and  is  not  affected 
by  light. 


92  ANALYSIS  OF  COPPER  ORES. 

Should  the  two  metals  co-exist,  they  will  both  be  pre- 
cipitated, and  must  be  separated  in  the  dry  way,  by 
cupellation,  hereafter  to  be  described. 

The  presence  of  gold  is  detected,  by  dissolving  the 
ore  in  aqua-regia,  (nitro  muriatic  acid,)  and  adding  a 
solution  of  sulphate  of  iron,  when  the  precious  metal 
falls  in  a  blackish  brown  powder.  Some  precautions 
are  necessary  in  this  process  to  insure  success.  The 
solution  must  be  carefully  evaporated  to  dryness  over 
the  water  bath,  and  then  moistened  with  hydrochloric 
acid.  This  process  must  be  repeated  several  times, 
until  no  more  fumes  of  nitrous  acid  are  given  off,  and 
the  solution  must  be  diluted. 

The  most  common  way  of  detecting  the  presence  of 
copper  in  a  mineral  is  to  dissolve  the  ore  in  boiling  aqua- 
regia,  filter  and  add  to  the  filtrate  a  solution  of  ammonia. 
Iron,  if  present,  falls  as  a  greenish  or  red-brown  mud, 
and  the  supernatant  liquor  has  a  very  fine  blue  color. 
Here  too  it  is  necessary  to  guard  against  mistakes. 
Nickel  also  gives  a  blue  solution  with  ammonia.  The 
experienced  eye,  however,  can  hardly  be  deceived,  for 
the  solution  of  nickle  is  a  pale  sapphire  blue,  while  that 
of  copper  is  a  deep  ultramarine.  Even  in  diluted  solu- 
tions, this  difference  is  observed. 

The  test  with  polished  iron  is  not  liable  to  these 
objections.  Even  in  very  dilute  solutions  of  copper,  a  knife 
blade  or  a  piece  of  clean  wire  is  so  completely  coated, 
that  it  appears  to  be  converted  into  copper.  One 
part  of  copper  in  180,000  of  solution  can  be  distinctly 
recognized  in  this  manner. 

In  some  rare  cases,  nitro-muriatic  acid  will  not  dis- 


ANALYSIS  OF  COPPER   ORES.  93 

solve  the  powdered  mineral  containing  copper.  It  is 
then  necessary  first  to  fuse  the  mineral  with  carbonate 
of  soda,  and  then  to  subject  it  to  the  action  of  the  acid 
and  proceed  as  before. 

The  blowpipe  methods  have  been  described  in  the  last 
chapter. 

A  common  way  of  determining  the  presence  of  copper 
in  an  ore  is  to  mix  it  with  carbonate  of  soda,  pearlash  or 
other  alkaline  flux,  intimately  mixed  with  finely  powdered 
charcoal,  and  to  heat  it  nearly  to  whiteness  in  a  crucible, 
by  the  fire  of  a  smith's  forge.  After  keeping  it  at  this 
heat  for  some  ten  or  fifteen  minutes,  or  until  the  con- 
tents of  the  crucible  are  in  quiet  fusion,  it  is  taken  off, 
allowed  to  cool,  and  when  the  crucible  is  broken,  a  but- 
ton of  copper,  enveloped  in  a  gray,  shining  coating  is 
usually  found  below  the  flux. 

It  can  hardly  be  necessary  to  say  that  in  all  these 
processes  it  is  necessary  that  the  ore  should  be  reduced 
to  the  finest  possible  powder,  before  it  is  subjected  to 
the  operations  recommended. 

If  it  be  designed  to  make  a  systematic  investigation 
of  all  the  contents  of  a  copper  ore,  the  following  methods 
should  be  resorted  to. 

The  ore  must  first  be  heated  gently  with  dilute  nitric 
acid,  as  before  described.  It  is  then,  after  everything 
soluble  in  the  dilute  acid  has  been  taken  up,  to  be  boiled 
with  concentrated  nitric  acid,  until  the  separated  sul- 
phur, if  there  be  any  present,  has  assumed  a  clear  yellow 
color.  These  two  solutions  are  poured  off  from  the 
insoluble  residue,  and  mixed  together  and  filtered.  We 
will  call  this  solution  No.  I.  Should  the  residue  be 


94  ANALYSIS  OF  COPPER  ORES. 

white,  and  it  be  desired  to  determine  the  presence  of 
the  earths,  it  must  be  boiled  with  hydrochloric  acid. 
Should  it  be  colored,  first  hydrochloric,  and  then  nitric 
acid  is  to  be  added  and  the  boiling  continued.  The 
whole  is  then  evaporated  to  dryness  over  a  water-bath,* 
moistened  with  hydrochloric  acid  and  drenched  with  dis- 
tilled water.  It  is  now  filtered  from  the  insoluble  resi- 
due, and  constitutes  solution  No.  II.  Should  the  residue 
still  be  colored,  it  is  to  be  washed  thoroughly  with  hot 
water,  and  treated  as  we  shall  presently  describe. 

To  the  solution  No.  I.  hydrochloric  acid  is  added. 
Should  a  white  precipitate,  which  does  not  dissolve  or 
diminish  on  the  further  addition  of  acid,  be  thrown  down, 
it  indicates  the  presence  of  lead,  mercury  or  silver,  or  all 
three.  It  must  be  well  washed  with  cold  water,  and 
then  heated  with  a  large  quantity  of  water.  If  sulphuric 
acid  throws  down  a  heavy  white  precipitate  from  this 
hot  solution,  the  presence  of  lead  is  established.  Should 
a  portion  remain  undissolved,  it  is  to  be  heated  gently 
with  excess  of  ammonia.  The  blackening  of  the  preci- 
pitate indicates  mercury.  The  ammoniacal  solution  is 
decanted  from  the  residue,  if  there  be  any,  and  mixed 
with  dilute  nitric  acid  until  a  piece  of  litmus  paper,  dip- 
ped into  it  becomes  red.  If  there  should  fall  a  white 
curdy  precipitate,  becoming  purple  by  exposure  to  light 
and  dissolving  in  ammonia,  silver  is  present. 

The  liquid  filtered  from  the  first  precipitate  is  added 
to  No.  II,  and  a  stream  of  sulphureted  hydrogen  gas  is 

*  This  can  easily  be  made  extemporaneously  by  placing  an  evapor- 
ating dish,  or  even  a  common  saucer,  over  a  tin  cup  containing  water, 
which  is  to  be  kept  boiling. 


ANALYSIS  OF  COPPER   ORES.  95 

passed  through  the  mixed  solutions.  This  is  obtained 
by  adding  dilute  sulphuric  acid  to  sulphuret  of  iron;* 
the  operation  being  conducted  in  a  bottle  fitted  with  a 
cork  and  a  bent  glass  tube  which  conveys  the  gas  into 
the  solution.  A  black  precipitate  immediately  falls,  and 
the  gas  is  passed  through  till  nothing  more  is  thrown 
down,  and  the  liquid  smells  strongly  of  it.  The  whole  is 
then  to  be  subjected  to  rapid  filtration,  taking  care  that 
during  the  whole  process  the  liquid  is  charged  with  sul- 
phureted  hydrogen,  which  may  be  known  by  the  smell.f 
The  filtrate  we  shall  call  solution  No.  III. 

The  sulphides  likely  to  be  found  in  the  precipitate,  are 
those  of  antimony,  arsenic,  bismuth,  cadmium,  copper 
and  gold.  The  latter  must  be  sought  in  the  original 
solution  as  already  described.  The  precipitate  being 
well  washed,  is  put  into  a  small  flask  and  boiled  with 
yellow  sulphide  of  ammonium,!  when  the  first  two  sul- 

*  This  re-agent  is  easily  obtained  by  heating  a  bar  of  iron  to  bright 
redness  and  holding  against  it  a  roll  of  brimstone.  Sparks  are  emitted 
and  globules  fall,  which  are  caught  in  a  pail  of  water.  These  are 
found  to  be  partly  yellow  and  partly  gray.  The  latter  are  selected. 
A  better  way  of  preparing  this  compound,  is  to  mix  intimately  36  parts 
of  clean  iron  filings  with  21  of  flowers  of  sulphur,  and  throw  them  by 
small  portions  at  a  time  into  a  red  hot  crucible. 

f  It  may  be  proper  to  state  here  that  writers  usually  recommend 
great  caution  in  manipulating  with  this  gas,  as  it  is  usually  reputed 
to  be  a  powerfully  sedative  poison.  I  think,  however,  that  its  danger- 
ous properties  have  been  considerably  exaggerated,  as  no  particular 
caution  has  ever  been  observed  in  its  use  in  my  laboratory,  and  no 
accident  has  occurred  there  from  it. 

J  This  reagent,  when  recently  prepared,  is  colorless,  but,  after 
standing  a  while,  becomes  yellow  or  even  red  from  separation  of 
sulphur.  The  latter  modification  differs,  in  some  essential  particulars, 
from  the  former. 


96  ANALYSIS  OF  COPPER   ORES. 

phides  will  be  dissolved.  The  solution  is  separated  by 
filtration  from  the  precipitate,  care  being  taken  to  Wash  the 
latter  thoroughly  with  water  charged  with  sulphide  of 
ammonium.  The  clear  filtrate  is  now  mixed  with  excess  of 
dilute  hydrochloric  acid,  and  a  little  water  saturated  with 
sulphureted  hydrogen.  The  sulphides  are  re-precipitated, 
and  after  being  thoroughly  washed,  are  agitated  with  a 
solution  of  carbonate  of  ammonia,  which  must  be  allowed 
to  remain  on  them,  at  a  gentle  heat,  for  about  fifteen 
minutes.  The  solution  contains  the  arsenic,  if  any  be 
present,  and  it  will  be  detected  by  the  yellow  precipitate 
which  falls  when  a  stream  of  sulphureted  hydrogen  is 
passed  through  the  liquid,  after  it  has  been  acidulated 
with  dilute  hydrochloric  acid.  The  precipitate,  after 
being  washed  with  solution  of  carbonate  of  ammonia  till 
a  yellow  precipitate  is  no  longer  produced  by  sulphur- 
eted hydrogen,  is  dissolved  off  the  filter  in  the  small- 
est possible  quantity  of  aqua  regia.  The  solution  is 
now  boiled  for  a  while  with  carbonate  of  ammonia  in 
excess,  and  acidulated  and  precipitated  as  before,  should 
this  precipitate  be  any  other  color  but  orange,  it  is 
because  of  the  presence  of  gold  or  copper.  In  this  case, 
it  must  be  collected  on  a  filter,  washed,  boiled  with 
strong  water  of  ammonia,  treated  with  a  few  bubbles  of 
sulphureted  hydrogen  and  filtered.  To  the  clear  solu- 
tion dilute  hydrochloric  acid  must  be  added,  and  a  stream 
of  sulphureted  hydrogen  passed  through  it,  when  an 
orange  precipitate  proves  the  presence  of  antimony. 

That  portion  of  the  precipitate  which  remained  undis- 
solved  in  sulphide  of  ammonium  is  now  examined  by 
heating  it  to  boiling  with  dilute  nitric  acid,  after  having 


ANALYSIS  OF  COPPER   ORES.  97 

first  thoroughly  washed  it.  The  solution  may  contain 
the  oxides  of  lead,  bismuth,  cadmium  and  copper.  It  is 
evaporated  to  a  small  bulk,  mixed  with  dilute  sulphuric 
acid,  allowed  to  stand  for  some  time  and  filtered  from 
any  precipitate  of  sulphate  of  lead  which  may  have  fal- 
len. The  solution  is  now  mixed  with  ammonia  till  the 
liquid  smells  strongly  of  it.  Should  a  precipitate  fall, 
it  is  bismuth.  This  may  be  proved  by  dissolving  the 
precipitate  in  dilute  nitric  acid,  adding  a  little  hydro- 
chloric acid,  evaporating  to  dryness,  re-dissolving  in  a 
little  water,  very  slightly  acidulated  with  hydrochloric 
acid,  and  then  adding  much  water,  when  a  milkiness 
indicates  the  presence  of  the  last  named  metal.  The 
solution,  filtered  from  the  precipitate  of  bismuth,  is  now 
to  be  acidulated  slightly  with  dilute  hydrochloric  acid, 
and  saturated  with  sulphureted  hydrogen.  The  result- 
ing precipitate  must  be  thoroughly  and  rapidly  washed, 
and  then  boiled  in  dilute  sulphuric  acid.  The  resulting 
solution  is  quickly  filtered  from  the  insoluble  matter, 
when,  if  cadmium  be  present,  it  may  be  known  by  the 
yellow  precipitate  which  sulphureted  hydrogen  throws 
down  from  the  clear  filtrate.  The  copper  remains  on 
the  filter  as  a  sulphide,  and  may  be  recognized  by  the 
tests  already  given. 

We  now  return  to  solution  No.  II.,  which  is  evapora- 
ted till  it  no  longer  smells  of  sulphureted  hydrogen, 
mixed  with  concentrated  nitric  acid,  and  evaporated  to 
dryness  on  a  sand  bath.  The  residue  is  digested  with 
hydrochloric  acid  on  a  sand  bath  until  it  is  white.  The 
solution  is  filtered  from  the  insoluble  silica ;  chloride  of 
ammonium  is  added,  then  strong  solution  of  ammonia, 


98  ANALYSIS  OF  COPPER,   ORES. 

and  lastly  sulphide  of  ammonium,  and  the  whole  is 
boiled  and  filtered.  The  precipitate  is  thoroughly 
washed  and  heated  with  dilute  hydrochloric  acid. 
Should  a  residue  remain  insoluble,  it  probably  contains 
cobalt  or  nickel.  The  whole  is  now  to  be  boiled  with 
nitric  acid,  diluted  with  water,  filtered,  mixed  with  ex- 
cess of  potassa,  boiled  and  filtered. 

The  precipitate,  after  being  well  washed,  is  dissolved 
in  warm,  dilute  hydrochloric  acid,  mixed  with  chloride 
of  ammonium  and  excess  of  ammonia,  and  rapidly 
filtered.  Before  this  is  done,  a  portion  of  the  precipi- 
tate should  be  dried,  and  fused,  before  the  blowpipe,  on 
platinum  foil  with  nitre  and  carbonate  of  soda.  A  green 
color  indicates  Manganese.  The  fused  mass  is  dissolved 
in  water,  the  solution  acidified  with  acetic  acid,  and 
mixed  with  a  solution  of  acetate  of  lead,  when  a  yellow 
precipitate  will  prove  the  presence  of  chronium.  The 
precipitate  from  the  last  addition  of  ammonia  is  dissol- 
ved in  dilute  hydrochloric  acid,  and  tested  with  ferro- 
cyanide  of  potassium.  A  blue  color  is  characteristic  of 
Iron.  The  ammoniacal  solution  is  acidified  by  hydrochlo- 
ric acid,  mixed  with  excess  of  carbonate  of  ammonia  and 
boiled.  If  a  precipitate  fall,  it  is  probably  Manganese, 
and  may  be  tested,  as  already  mentioned,  by  the  blow- 
pipe. 

If  any  cobalt  and  nickel  be  present,  they  are  con- 
tained in  the  solution,  which  is  to  be  mixed  with  solution 
of  cyanide  of  potassium  as  long  as  any  change  of  color 
is  observed ;  then  treated  with  excess  of  hydrochloric 
acid  and  boiled  till  no  more  fumes  of  hydrocyanic  acid 
are  given  off.  Potassa  is  now  added  in  excess,  and  the 


ANALYSIS  OF  COPPER  ORES.  99 

solution  is  boiled  till  no  more  ammonia  escapes.  The 
precipitate  is  probably  oxide  of  nickel,  which  must  be 
tested  before  the  blowpipe.  The  solution  is  now  acidu- 
lated with  nitric  acid,  evaporated  to  dryness,  the  residue 
fused  for  some  minutes,  allowed  to  cool,  and  then  heated 
with  water.  Should  a  black  substance  remain,  it  is  well 
washed,  dried,  and  fused  in  the  blowpipe  flame  with 
potassa.  A  blue  color  indicates  cobalt. 

The  colored  residue  from  solution  No.  II.  is  now 
mixed  with  about  four  times  its  weight  of  a  dried  mix- 
ture of  the  carbonates  of  potassa  and  soda,  and  placed  in 
a  porcelain  crucible,  which  is  itself  enclosed  in  a  Hes- 
sian crucible.  If  it  is  desired  to  protect  the  porcelain 
crucible  as  fully  as  possible  from  too  sudden  changes  of 
temperature,  the  Hessian  crucible  may  be  filled  with 
calcined  magnesia,  which  is  to  be  rather  tightly  packed. 
This  precaution,  however,  is  not  absolutely  necessary, 
though  by  furnishing  a  more  equable  heat  to  all  parts 
of  the  inner  crucible,  it  diminishes  the  risk  of  fracture. 
The  outer  crucible  is  now  covered  with  a  small  piece  of 
brick,  which  should  fit  it  with  tolerable  accuracy,  the 
inner  crucible  having  been  closed  with  its  own  appro- 
priate lid.  Thus  prepared,  the  crucible  is  introduced 
into  the  fire  of  a  forge,  or  even  a  common  coal  stove, 
and  heated  gradually  to  bright  redness.  This  tempera- 
ture is  to  be  maintained  for  about  twenty  minutes,  when 
upon  the  withdrawal  of  the  crucible,  the  mixture  within 
will  be  found  fused  to  a  glass,  with  a  smooth,  depressed 
surface.  Should  this  not  be  the  case,  it  is  an  indication 
that  the  substance  has  not  been  sufficiently  heated,  in 
which  case  it  must  be  returned  to  the  fire,  and  kept 


100  ANALYSIS  OF  COPPER    ORES. 

there  till  it  assumes  the  appearance  described,  and  then 
allowed  to  cool. 

The  porcelain  crucible  is  now  removed,  carefully  freed 
from  every  adhering  particle  of  magnesia,  placed  in  a 
large  beaker,  and  digested  with  distilled  water  in  a 
warm  place.  As  soon  as  the  fused  mass  is  loosened,  it 
is  removed,  and  its  lower  surface  examined  for  globules 
of  metal,  which,  however,  will  rarely,  if  ever,  be  found, 
should  the  preceding  operations  have  been  properly 
conducted.  The  fused  mass  should  be  treated  first  with 
nitric  and  then  with  hydrochloric  acids,  and  examined 
precisely  in  the  manner  already  described  for  the  ori- 
ginal ore. 

If  it  be  desired  to  ascertain  the  earthy  constituents  of 
the  ore,  a  matter  of  no  little  importance  to  the  smelter, 
a  further  series  of  operations  will  be  necessary.  A  por- 
tion of  the  solution  resulting  from  the  ebullition  with 
potassa,  in  solution  No.  II.,  is  tested  for  alumina,  by 
mixing  it  with  excess  of  ammonia,  and  heating  it,  when, 
if  that  earth  be  present,  a  white  precipitate  will  fall. 
If,  after  filtering,  the  clear  solution  give  a  white  pre- 
cipitate with  sulphide  of  ammonium,  the  ore  contains 
zinc. 

The  other  earths  will  be  found  in  the  precipitate  ob- 
tained by  the  addition  of  potassa.  After  dissolving  it 
in  hydrochloric  acid,  precipitating  with  chloride  of  am- 
monium and  excess  of  ammonia,  the  earth,  should  no 
phosphates  be  present,  will  be  found  in  the  solution. 
Should  phosphates  be  present,  it  will  be  necessary  to 
dissolve  the  precipitate  in  dilute  hydrochloric  acid,  mix 
the  solution  with  acetate  of  potassa,  add  sesquichloride 


ANALYSIS  OF  COPPER   ORES.  101 

of  iron  till  a  red  color  appears,  boil  and  filter.  The 
phosphoric  acid  remains  with  the  iron  upon  the  filter, 
while  the  chlorides  of  the  earth  pass  through,  and  are 
found  in  the  filtrate. 

They  are  easily  detected  by  the  following  process :  If 
the  solution  be  colored,  it  must  be  mixed  with  chloride 
of  ammonium,  ammonia,  and  sulphide  of  ammonium, 
boiled  and  filtered,  care  being  taken  that  during  the 
whole  process  it  smells  strongly  of  the  last  named 
reagent.  The  clear  solution  is  boiled  to  expel  sulphide 
of  ammonium,  and  mixed  with  excess  of  carbonate  of 
ammonia.  The  white  precipitate  is  collected  on  a  filter, 
and  the  solution  treated  with  phosphate  of  soda.  A 
white  precipitate  indicates  magnesia.  The  precipitate 
is  dissolved  in  dilute  hydrochloric  acid,  and  divided  into 
three  parts.  To  the  first  portion,  sulphate  of  lime  in 
solution  is  added.  An  immediate  white  precipitate  indi- 
cates baryta.  The  second  portion  is  mixed  with  a  satu- 
rated solution  of  sulphate  of  potassa,  and  allowed  to 
stand  till  the  precipitate  settles,  care  being  taken  to  add 
enough  thoroughly  to  precipitate  all  the  baryta  and 
strontia  present.  The  mixture  is  now  filtered,  and  am- 
monia and  oxalate  of  ammonia  added  to  the  filtrate.  A 
white  precipitate  shows  the  presence  of  lime.  The  third 
solution  is  mixed  with  excess  of  hydrofluosilicic  acid, 
filtered  if  necessary,  evaporated  to  dryness,  and  extracted 
with  water,  which  must  remain  a  long  time  in  contact 
with  it.  The  solution  thus  obtained  is  filtered,  mixed 
with  sulphate  of  lime  in  solution,  and  allowed  to  stand 
for  some  time,  when,  should  a  precipitate  form,  it  is  in- 
dicative of  strontia. 

9* 


102  ANALYSIS  OF  COPPER   ORES. 

QUANTITATIVE  ANALYSIS. 

Copper  is  commonly  estimated  in  the  form  of  oxide, 
and*  the  agent  used  to  precipitate  it  from  its  solutions  is 
a  solution  of  pure  caustic  potash.  Some  precautions 
are  necessary  in  order  to  insure  the  success  of  this  pro- 
cess. The  copper  solution  is  boiled  in  a  porcelain  or 
platinum  capsule,  and  the  potash  is  added  during  ebul- 
lition, till  it  no  longer  produces  a  precipitate.  Oxide  of 
copper  falls  in  the  form  of  a  heavy  brownish  black  powder. 

Before  filtering,  it  is  necessary  to  dilute  the  liquor 
and  boil  it,  for  if  it  be  too  concentrated,  some  hydrated 
blue  oxide  remains  suspended  in  the  solution,  and  is  not 
precipitated  by  boiling.  The  boiling  also  is  essential, 
for  should  potash  be  added  to  a  solution  of  copper  in 
the  cold,  the  precipitate  is  blue,  bulky,  and  mixed  with 
alkali,  which  it  is  very  difficult  to  wash  out.  Boiling 
will  convert  this  loose  hydrate  to  the  dense  black  pro- 
toxide. 

In  any  case,  protoxide  of  copper  is  very  difficult  to 
wash,  but  it  may  be  entirely  freed  from  potash  by  using 
hot  water.  The  cleansing  is  facilitated  by  filtering  in  an 
atmosphere  of  steam.  This  is  conveniently  done  in  Nor- 
mandy's filtering  apparatus,*  but  any  person  of  common 
ingenuity  will  be  able  to  contrive  means  of  accomplish- 
ing this.  After  complete  washing,  the  precipitate  is 
thoroughly  dried.  For  this  purpose,  I  am  in  the  habit 
of  employing  an  air  oven,  attached  to  my  stove.  It  is 
made  of  sheet  iron,  and  fitted  in  the  stove  under  the 

*  See  Normandy's  edition  of  Rose's  Treatise  on  Chemical  Analysis, 
vol.  ii.  p.  33. 


ANALYSIS  OF  COPPER  ORES.  103 

pipe.  It  is  provided  with  several  sheet  iron  shelves, 
perforated  with  holes  to  receive  the  necks  of  the  funnels. 

After  drying,  the  filter  is  removed  from  the  funnel, 
and  separated  from  the  precipitate.  This  is  best  accom- 
plished by  placing  the  platinum  crucible  in  which  the 
ignition  is  to  be  performed,  on  the  central  angles  of 
four  quarter  sheets  of  glazed  paper,  laid  together,  and 
emptying  the  precipitate  into  it.  Some  of  the  ox- 
ide will  adhere  to  the  filter ;  this  is  to  be  removed  by 
gently  rubbing  the  filter  between  the  fingers,  over  the 
crucible.  With  all  these  precautions,  some  small  parti- 
cles of  the  oxide  will  still  adhere  to  the  filter.  To  avoid 
the  loss  of  these,  the  filter  is  to  be  cut  up  with  a  sharp 
pair  of  scissors,  and  dropped  into  the  crucible,  or  it  may 
be  burned  separately  upon  the  cover,  or  still  better, 
rolled  into  a  corner,  wrapped  with  a  few  turns  of  thin 
platinum  wire,  and  burned  in  the  open  air.  The  crucible 
is  now  removed  to  the  centre  of  one  of  the  pieces  of 
paper,  and  the  oxide  which  has  been  spilled,  carefully 
tilted  into  it. 

The  ignition  may  be  accomplished  either  over  an  alco- 
hol lamp,  over  gas  flame,  or  in  the  furnace.  Should 
the  former  be  preferred,  a  Berzelius  or  Rose  lamp 
should  be  selected.  The  flame  at  first  should  be  very 
low,  until  the  paper  has  been  slowly  charred,  after 
which  it  is  to  be  gradually  raised  till  the  crucible  is  red 
hot,  and  kept  at  that  till  the  paper  has  burned  white. 
Care  must  be  taken  that  the  white  flame  of  the  lamp 
does  not  touch  the  sides  of  the  crucible,  or  it  will  injure 
the  metal.  If  the  fire  be  chosen,  the  crucible  must  be 
placed  in  a  Hessian  crucible,  lined  with  magnesia,  as 
already  described. 


104  ANALYSIS  OF  COPPER   ORES. 

The  ignition  of  the  filter  will  usually  reduce  a  portion 
of  the  oxide  to  the  metallic  state  ;  but  this  may  easily 
be  oxidized  by  directing  a  current  of  air  upon  it  during 
the  ignition.  Sufficient  draft  for  this  purpose  may  be 
obtained  by  placing  in  the  crucible  a  piece  of  platinum 
foil  in  the  form  of  a  partition.  A  still  better  method  is 
to  allow  the  whole  to  cool,  to  moisten  with  a  few  drops 
of  nitric  acid,  and  then  to  ignite  the  second  time. 

After  ignition,  the  crucible  must  be  weighed  as  soon 
as  possible,  or  it  will  absorb  water  from  the  atmosphere. 
It  should  not  be  weighed  hot,  but  immediately  after 
cooling.  It  is  best  to  cool  it  under  a  bell  glass,  sup- 
ported over  a  dish  of  concentrated  sulphuric  acid. 
Every  100  parts  are  equal  to  79.83  of  metallic  cop- 
per. 

Sometimes  the  potash  does  not  precipitate  all  the 
copper  from  its  solution,  a  state  of  affairs  which  may  be 
recognized  by  the  brown  discoloration  of  the  liquid  pro- 
duced by  sulphide  of  ammonium.  Again,  after  pro- 
tracted boiling  with  potash,  some  protoxide  of  copper 
adheres  to  the  sides  of  the  capsule  in  which  the  precipi- 
tation has  been  effected,  and  cannot  be  separated  by 
mechanical  means.  When  this  occurs,  the  adhering 
oxide  must  be  dissolved  in  a  little  dilute  sulphuric  acid, 
and  precipitated  as  before,  water  being  previously 
added.  In  very  dilute  solutions,  this  accident  never 
happens. 

This  process  can  be  used  in  ammoniacal  solutions,  pro- 
vided they  be  well  boiled  and  rapidly  filtered  from  the 
precipitate.  If  the  ammoniacal  liquor  be  allowed  to 
stand  too  long  upon  the  precipitate,  it  will  inevitably 


ANALYSIS  OF  COPPER    ORES.  105 

re-dissolve  some  of  the  oxide,  and  the  liquid  would  be- 
come blue.  It  should  be  altogether  colorless  during  the 
filtration. 

Carbonate  of  potash  cannot  be  substituted  for  caustic 
potash  in  these  determinations,  because  it  leaves  in  solu- 
tion some  protoxide  of  copper,  which  can  only  be  sepa- 
rated by  evaporating  the  liquor  to  dryness,  and  igniting 
the  salt. 

The  copper  may  also  be  determined  in  the  metallic 
state  by  introducing  into  the  solution  a  perfectly  clean, 
polished  piece  of  metallic  iron.  Much  objection  has 
been  made  to  this  process,  on  various  grounds,  by  differ- 
ent chemists.  It  has  been  said  that  it  is  liable  to  be 
contaminated  with  the  carbon  and  fibrous  flakes  of  iron, 
which  will  vitiate  the  result,  and  that  in  drying  it,  a 
suboxide  of  copper  will  be  formed,  which  will  exagge- 
rate the  per  centage. 

These  objections  may  be  of  force  in  the  more  delicate 
determinations  of  copper,  when  absolute  scientific  accu- 
racy is  required,  but  as  far  as  the  commercial  analysis 
of  ores  is  concerned,  they  have  no  substantial  founda- 
tion, if  proper  care  be  taken.  In  the  first  place,  rolled 
iron  should  not  be  employed,  or  the  carbon  separated 
will  be  considerable,  and  the  fibrous  pieces  detached 
during  the  operation,  numerous.  I  am  in  the  habit  of 
using  bright  piano  wire,  which  I  roll  into  a  spiral  coil, 
and  introduce  into  the  liquid.  Secondly,  the  solution 
of  copper  must  be  dilute,  and  decidedly  acid.  If  it  be 
too  concentrated,  all  the  copper  will  not  be  precipitated, 
and  if  it  be  not  sufficiently  acidulated,  an  insoluble  ba- 
sic salt  of  iron  will  mix  with  the  copper,  and  ruin  the 


106  ANALYSIS  OF  COPPER   ORES. 

analysis.  Thirdly,  the  precipitate,  after  being  tho- 
roughly washed,  must  be  dried,  at  a  very  moderate 
heat.  Mitchell  says  it  must  not  be  raised  above  212°. 
I  have  been  in  the  habit  of  drying  my  precipitates  in 
an  air  oven,  at  a  temperature  of  about  150°  F.,  and 
I  have  never  been  troubled  with  oxidation.*  Fourthly, 
there  must  be  no  free  nitric  acid  in  the  solution  ;  and, 
lastly,  the  precipitate  must  be  very  thoroughly  washed. 
Mitchell  prefers  zinc  to  iron  for  these  operations,  but 
I  am  of  different  opinion.  I  have  frequently  used  the 
zinc,  and  have  always  been  disappointed.  It  throws 
down  the  copper  in  a  pasty  state,  from  which  the  zinc 
salt  is  not  easily  separated,  and  which,  owing  to  its  ex- 
tremely minute  division,  oxidates  rapidly,  during  drying. 
Mitchell's  reason  for  preferring  the  zinc,  is  the  sup- 
posed contamination  of  the  precipitated  copper  by  the 
separated  carbon  and  detached  fibres  of  the  iron.  This, 
however,  depends  entirely  upon  the  kind  of  iron  opera- 
ted with,  and  the  acidity  of  the  solution.  If  bar  iron 
or  cut  nails  be  used,  the  operator  will  have  trouble 
enough  from  this  source ;  but  should  he  employ  good 
clean  piano  wire,  he  will  not  be  able  to  estimate  or  de- 
tect the  carbon.  It  is  also  desirable  to  use  large  excess 
of  iron,  as  then  there  will  be  no  risk  of  annoyance  from 
little  detached  filaments  of  that  metal,  and  if  the  solu- 
tion have  been  properly  acidulated,  the  copper  will 
separate  in  brilliant  scales,  the  under  surface  of  which 

*  Even  if  oxidation  should  take  place,  the  assayer  need  not  reject 
his  result,  and  so  lose  his  labor.  The  error  is  easily  rectified  by  pla- 
cing the  whole  in  a  tray  of  platinum  foil,  introducing  it  into  a  tube  of 
hard  glass,  and  igniting  in  a  current  of  washed  hydrogen  gas. 


ANALYSIS  OP  COPPER    ORES.  107 

coming  off  from  the  iron,  will  be  clean  and  polished. 
If,  however,  bar  iron  have  been  employed,  or  too  much 
acid  used,  the  under  surface  of  the  copper  is  frequently 
black  with  carbon,  and  roughened  by  detached  fibres  of 
iron.  Under  such  circumstances,  it  is  needless  to  say 
that  the  process  cannot  be  relied  upon,  for  though  the 
iron  may  be  separated  by  dilute  hydrochloric  acid, 
some  loss  of  copper  will  probably  ensue,  and  the  carbon 
cannot  be  got  rid  of.  If  the  solution  be  only  slightly 
acidulated,  a  sort  of  galvanic  action  sometimes  takes  place 
between  the  iron  and  the  first  particles  of  copper  precipi- 
tated, so  that  the  copper  is  deposited  in  a  firm  sheet,  and 
sometimes  is  so  closely  adherent  to  the  positive  metal  as 
to  be  inseparable  from  it  by  mechanical  means.  If,  on 
the  other  hand,  the  solution  be  too  strongly  acid,  there 
is  more  danger  from  contamination  from  carbon. 

The  time  taken  up  by  this  process  varies  with  the 
temperature  at  which  it  is  conducted.  If  the  precipita- 
tion takes  place  at  the  common  temperature  of  the  air, 
it  will  require  from  twelve  to  twenty-four  hours  for  its 
completion.  The  heat  of  a  sand  bath  accelerates  the 
deposition  of  the  copper,  and  if  the  solution  be  made  to 
boil,  all  the  copper  is  thrown  down  in  an  hour.  The 
operator  usually  determines  the  end  of  his  process  by 
the  solution  becoming  colorless,  or  assuming  a  scarcely 
perceptible  beryl  green  hue.  A  better  plan,  however, 
is  to  introduce  a  piece  of  clean  polished  iron  into  the 
solution.  If,  after  some  minutes,  it  remain  uncolored, 
the  copper  may  be  considered  precipitated. 

Levol  suggested  a  method  of  estimating  the  quantity 
of  copper  in  a  solution  containing  it,  which  is  employed 


108  ANALYSIS  OF  COPPER  ORES. 

by  many  chemists.  After  getting  the  nitric  or  nitro- 
muriatic  solution,  he  supersaturates  with  ammonia,  and 
pours  it  into  a  flask  or  bottle,  which  can  be  closed  air- 
tight with  a  ground  glass  stopper,  or  in  any  other  way. 
Cork  must  not  be  used  for  this  purpose,  as  its  porous 
nature  allows  air  to  traverse  it,  and  so  vitiates  the  re- 
sult. Some  operators  close  the  mouth  of  the  vessel  by 
tying  a  bit  of  sheet  India  rubber  over  it,  so  as  thoroughly 
to  exclude  the  air.  Should  the  ammoniacal  liquor  fail  to 
fill  the  bottle,  water,  from  which  all  atmospheric  air  has 
been  excluded  by  recent  boiling,  is  introduced  till  the 
vessel  employed  is  completely  filled.  A  clean,  bright 
blade  of  pure  copper,  which  has  been  carefully  weighed, 
is  now  introduced  into  the  whole  length  of  the  vessel, 
which  is  immediately  closed.  The  whole  is  set  aside 
till  the  liquor  becomes  colorless,  in  consequence  of  the 
formation  of  a  suboxide  of  copper  by  the  action  of  the 
metal  upon  the  protoxide  in  solution.  The  blade  is  then 
quickly  withdrawn,  washed  in  distilled  water,  dried,  and 
weighed.  The  loss  sustained  by  the  blade  indicates  the 
amount  of  metallic  copper  present,  for  CuO+Cu=Cu20. 
One  equivalent  of  copper  has  abandoned  the  blade  and 
formed  a  suboxide. 

I  have  never  been  able  to  get  good  results  from  this 
process.  It  is,  in  the  first  place,  extremely  tedious. 
Its  author  says  it  is  finished  in  four  days,  but  I  have 
had  bottles  standing  on  my  shelves  for  two  weeks  in  hot 
summer  weather,  and  still  remaining  blue.  Some  che- 
mists say  that  the  process  can  be  greatly  hastened,  so 
as  to  be  completed  in  an  hour  or  two,  by  closing  the 
mouth  of  the  vessel  with  sheet  caoutchouc,  and  heating 


ANALYSIS  OF  COPPER    ORES.  109 

in  a  water  bath.  This  method  is  manifestly  inapplicable 
in  the  presence  of  silver,  and  other  metals,  soluble  in 
ammonia  and  precipitable  by  metallic  copper. 

Cassaseca  proposed  a  method  which  can  only  be  re- 
garded as  a  rough  approximative  estimation.  He  com- 
pares the  tint  of  an  amrnoniacal  solution  of  the  sub- 
stance under  examination  with  that  of  another 
ammoniacal  liquid  containing  a  known  weight  of  pure 
copper. 

Copper  is  also  precipitated  as  sulphide  by  sulphuret- 
ed  hydrogen,  or  by  an  alkaline  sulphide.  It  cannot, 
however  be  weighed  as  a  sulphide,  because  in  drying, 
and  even  during  washing,  it  absorbs  oxygen  from  the 
air.  For  this  reason,  it  is  dissolved  in  aqua  regia  or 
nitric  acid,  and  precipitated  as  oxide. 

Pelouze  contrived  a  volumetrical  process  for  estima- 
ting this  metal.  It  consists  in  precipitating  the  copper 
from  its  ammoniacal  solution  by  means  of  a  standard 
solution  of  sulphide  of  sodium.  This  salt,  the  colorless 
crystallized  hydrosulphate  of  commerce,  is  dissolved  in 
distilled  water,  and  introduced  into  a  graduated  tube  or 
burette,  divided  into  tenths  of  cubic  centimetres.  To 
determine  the  value  of  this  standard  solution,  it  is  neces- 
sary to  dissolve  a  certain  quantity  of  pure  copper,*  say 
a  gramme,  in  pure  nitric  acid,  and  supersaturate  it 
with  ammonia  until  a  perfectly  clear  blue  solution 
be  obtained.  This  is  raised  to  the  boiling  point,  and 
the  test  solution  dropped  into  it.  The  copper  is  pre- 
cipitated as  sulphide,  and  the  liquor  gradually  fades. 

*  That  obtained  by  the  electrotype  process  is  generally  preferred. 

10 


110  ANALYSIS  OF  COPPER   OKES. 

Dilute  water  of  ammonia  is  added  from  time  to  time,  to 
replace  that  which  is  lost  by  evaporation,  and  towards 
the  close  of  the  operation,  the  solution  is  let  fall  from 
the  burette,  in  single  drops,  the  flask  containing  the 
copper  salt  having  been  shaken  repeatedly  during  the 
operation.  As  soon  as  the  solution  is  completely  deco- 
lorized, the  number  of  degrees  is  read  off  from  the 
burette,  and  recorded,  for  the  sake  of  comparison. 

The  substance  to  be  examined  is  now  dissolved  in 
aqua  regia,  treated  with  ammonia,  and  decolorized,  pre- 
cisely in  the  same  manner  as  the  solution  of  pure  copper. 
The  decrease  in  the  blue  color  indicates  the  progress  of 
the  precipitation,  and  as  the  period  of  complete  decolo- 
ration approaches,  it  is  desirable  to  add  the  test  solution 
in  drops,  or  even  to  employ  the  same  solution  more 
largely  diluted  with  a  known  quantity  of  water.  The 
number  of  degrees  must  be  read  off  as  soon  as  the 
decoloration  is  accomplished,  because  the  precipitated 
sulphide  is  soon  oxidated  to  sulphate,  which  is  again 
dissolved  in  the  ammonia,  rendering  it  blue,  so  that  the 
operator,  who  delays  too  long,  will  go  on  re-precipitating 
the  same  copper,  and  getting,  of  course,  too  large  a 
per  centage. 

A  comparison  of  the  two  readings  of  the  burette  will 
give  the  proportion  of  copper  in  the  substance  analyzed. 
Thus,  if  500  measures  of  the  test  solution  decolorize  an 
ammoniacal  liquor  containing  one  gramme  of  pure  copper, 
and  the  liquid  under  examination  require  480  measures 
to  discharge  its  color,  it  follows  that  it  contains  f  $§•  or 
0.96  of  a  gramme. 

This   method,   according  to  the  author,  is  liable  to 


ANALYSIS  OF  COPPER    ORES.  Ill 

error  of  not  more  than  five  or  six  thousandths.  It  is 
not  interfered  with  hy  the  presence  of  tin,  zinc, 
cadmium,  lead,  antimony,  iron,  arsenic,  or  bismuth,  as 
the  copper  always  falls  before  these  other  metals.  In- 
deed, it  has  been  asserted  that  when  the  sulphurets  of 
zinc,  cadmium,  tin,  lead,  antimony,  and  bismuth,  are 
placed  in  contact  with  an  ammoniacal  solution  of  sul- 
phate of  copper,  they  decolorize  it,  which  proves  that 
they  cannot  exist,  except  for  a  moment,  in  a  solution 
of  copper.  Iron  should  be  peroxodized  before  the  addi- 
tion of  the  ammonia,  by  ebullition  with  nitric  acid, 
unless  the  solution  should  have  been  made  in  aqua  re- 
gia.*  It  need  not  be  filtered,  some  chemists  say;  but 
it  is  a  slovenly  way  of  working  to  decolorize  a  solution 
with  a  large  magma  diffused  through  it.  Should  there 
be  a  large  quantity  of  iron  present,  the  solution  must 
be  filtered,  or  it  will  be  impossible  accurately  to  deter- 
mine the  moment  of  decoloration,  and  in  all  instances 
it  is  best  to  filter.  The  other  sulphurets  go  down  after 
the  copper.  If  zinc  alone  be  present,  a  white  precipi- 
tate falls  ;  if  cadmium,  a  brilliant  yellow  one  goes  down 
immediately  after  the  decoloration  has  been  effected  by 
the  precipitation  of  all  the  copper. 

This  method  is  of  course  inapplicable  in  the  presence 
of  cobalt,  nickel,  and  mercury,  and  also  when  silver  is 
mixed  with  the  copper.  The  latter  metal,  however, 
can  easily  be  separated  by  hydrochloric  acid  and  filtra- 
tion, before  the  ammoniacal  solution  is  made. 

It  is  necessary,  in  all  cases,  to  estimate  the  strength 

*  This  is  a  matter  of  great  importance,  for  should  any  of  the  iron 
remain  in  the  form  of  protoxide,  it  will  vitiate  the  result,  that  oxide 
being,  to  a  certain  extent,  soluble  in  ammonia. 


112  ANALYSIS  OF  COPPEE   ORES. 

of  the  standard  solution  of  sulphide  of  sodium,  before 
each  series  of  analyses,  for  this  substance  is  slowly  oxi- 
dated by  exposure  to  the  air,  and  consequently  becomes 
weaker  as  it  grows  older. 

SEPARATION  OF  OXIDE  OF  COPPER  FROM  OXIDE  OF  BISMUTH. 

The  agent  commonly  employed  in  separating  copper 
from  bismuth  is  carbonate  of  ammonia,  which  when 
added  in  excess,  dissolves  the  copper  and  throws  down 
the  bismuth.  After  the  precipitation,  it  should  not  be 
immediately  filtered,  but  should  be  allowed  to  stand  for 
some  time  in  a  warm  place,  to  enable  the  oxide  of 
bismuth  completely  to  subside.  The  latter  oxide  is  to 
be  well  washed  on  the  filter  with  carbonate  of  ammonia. 
The  filtrate  is  now  evaporated  at  a  gentle  heat,  to  expel 
the  excess  of  carbonate  of  ammonia,  treated  with  ammo- 
nia and  precipitated,  as  already  described,  by  caustic 
potash.  The  oxide  of  bismuth  is  ignited  and  weighed. 
This  method  is  not  unexceptionable,  it  being  difficult  to 
separate  the  last  traces  of  copper  from  the  bismuth. 

Cyanide  of  potassium  has  been  used  for  this  purpose. 
A  slight  excess  of  carbonate  of  ammonia  having  been 
added  to  the  solution  of  the  two  oxides,  it  is  heated  with 
cyanide  of  potassium.  Carbonate  of  bismuth  falls,  and 
the  copper  remains  in  solution.  The  mixture  is  filtered, 
the  filtrate  evaporated  with  sulphuric  acid,  to  expel  the 
hydrocyanic  acid,*  and  the  copper  precipitated  by  caus- 
tic potash. 

*  This  operation  should  always  be  performed  under  a  hood,  in  a 
strong  draught,  as  the  fumes  of  the  hydrocyanic  acid  are  a  deadly 
poison.  If  the  operator  has  no  hood,  he  should  work  in  the  open 
air,  or  with  his  back  towards  a  strong  draught. 


ANALYSIS  OF  COPPER    ORES.  113 

Another  method  is  to  precipitate  the  two  metals  as 
sulphides,  and  having  well  washed  and  weighed  the 
mixed  sulphides,  to  introduce  them  into  a  glass  tube, 
connected  at  one  end  with  an  apparatus  for  generating 
chlorine,  and  at  the  other,  by  means  of  a  bent  tube  dip- 
ping under  the  surface,  with  a  vessel  containing  water 
acidulated  with  hydrochloric  acid.  A  stream  of  chlorine 
being  passed,  the  sulphides  are  heated  by  a  spirit  lamp, 
first  gently,  and  afterwards  to  redness.  The  sulphides 
are  thus  converted  to  chlorides.  The  chloride  of  bis- 
muth, being  volatile,  distils  over  and  is  dissolved  in  the 
acidulated  water,  while  the  fixed  chloride  of  copper 
remains  in  the  tube.  It  is  to  be  washed  out  with  a  little 
dilute  nitric  acid,  evaporated  with  sulphuric  acid,  and 
estimated  as  before. 

If  the  substance  treated  be  an  alloy,  it  may  be  directly 
acted  upon  by  the  chlorine. 

SEPARATION  OF  PROTOXIDE  OF  COPPER  FROM  PROTOXIDE 
OF  LEAD. 

Copper  is  often  separated  from  lead  by  boiling  the 
solution  of  the  mixed  oxides  with  one  of  caustic  potash. 
The  process  is  an  imperfect  one,  leaving  always  some 
lead  mixed  with  the  copper. 

Carbonate  of  ammonia  has  been  employed  for  the 
same  purpose.  The  solution  is  mixed  with  excess  of 
this  reagent,  carbonate  of  lead  is  precipitated,  and 
copper  remains  in  solution.  A  portion  of  the  copper, 
however,  goes  down  with  the  carbonate  of  lead,  giving  a 
greenish  hue  to  that  salt,  which,  when  pure,  is  of  a  clear, 
brilliant  white. 

10* 


114  ANALYSIS  OF  COPPER   ORES. 

Sulphuric  acid  is  the  agent  commonly  employed  for 
this  purpose.  Into  the  concentrated  solution  dilute 
sulphuric  acid  is  poured  as  long  as  a  precipitate  falls ; 
alcohol  is  then  added.  The  precipitate  is  collected  on  a 
filter,  and  washed,  first  with  dilute  sulphuric  acid,  and 
then  with  alcohol.  Sometimes,  after  the  precipitation, 
the  whole  is  evaporated  to  dryness,  and  the  mass  heated 
to  expel  excess  of  sulphuric  acid.  This  is  thrown  upon 
a  filter,  well  washed,  dried,  and  ignited,  and  the  copper 
is  subsequently  precipitated  with  potash.  If  the  alco- 
hol have  been  used,  it  is  necessary  first  to  evaporate  the 
copper  solution,  so  as  to  expel  this  volatile  liquid  before 
precipitating  with  potash. 

A  little  lead  may  escape,  as  the  sulphate  of  this  metal 
is  not  altogether  insoluble  in  water.  This,  however, 
will  always  be  found,  if  the  process  has  been  carefully 
conducted,  in  the  filtrate  from  the  precipitated  oxide  of 
copper,  and  may  be  precipitated  as  oxalate  by  oxalate 
of  ammonia,  after  having  previously  neutralized  the 
solution  with  a  little  dilute  acid. 

Cyanide  of  potassium  is  used  for  separating  lead,  in 
the  same  manner  as  already  described  for  bismuth. 
Copper  has  also  been  separated  from  lead  by  using 
hydrochloric  acid,  and  precipitating  the  last  traces  of 
chloride  of  lead  with  a  strong  alcohol.  The  rest  of  the 
process  is  conducted  as  before  described,  when  speaking 
of  the  management  of  the  sulphuric  acid  process  with 
alcohol. 

SEPARATION  OF  OXIDE  OF  SILVER  FROM  OXIDE  OF  COPPER. 

Silver  is  easily  separated  from  a  solution  of  the  mixed 
oxides  in  nitric  acid  by  the  addition  of  hydrochloric  acid. 


ANALYSIS  OF  COPPER    ORES.  115 

The  chloride  of  silver  is  collected  on  a  filter,  washed  by 
a  continuous  stream  of  water,  dried,  and  fused  in  a 
porcelain  crucible.  The  copper  is  precipitated  from  the 
filtrate  by  potash. 

Or  the  solution  of  metals  may  be  treated  with  cyanide 
of  potassium  till  the  precipitate  first  formed  is  entirely 
re-dissolved,  the  solution  having  previously  been  neutral- 
ized with  potassa.  On  the  addition  of  pure  nitric  acid 
to  the  clear  solution,  all  the  silver  is  thrown  down  as 
cyanide.  The  filtrate  is  evaporated  with  sulphuric  acid, 
to  expel  hydrocyanic  acid,  and  the  copper  precipitated 
as  oxide  by  potassa. 

Fresenius  uses  this  reagent  somewhat  differently. 
Having  obtained  the  cyanide  solution,  he  passes  through 
it  a  stream  of  sulphureted  hydrogen,  which  throws 
down  silver  only,  provided  enough  cyanide  of  potassium 
be  present.  The  solution  is  filtered  from  the  sulphuret 
of  silver,  heated  to  expel  sulphureted  hydrogen,  treated 
again  with  cyanide  of  potassium,  evaporated  with  a 
mixture  of  sulphuric  and  nitric  acids,  and  precipitated 
with  potassa. 

SEPARATION  OP  COPPER  FROM  MERCURY.     - 

"When  the  mixed  oxides  are  dry,  they  are  easily  sepa- 
rated by  ignition,  the  mercury  volatilizing,  and  leaving 
the  copper.  When  in  solution,  the  mixed  oxides  may 
be  treated  with  cyanide  of  potassium,  in  the  manner 
already  described  for  silver.  Sulphureted  hydrogen, 
passed  through  this  solution,  throws  down  the  mercury 
alone. 

Formiate  of  soda  is  another  agent  which  has  been 


116  ANALYSIS  OF  COPPER  ORES. 

employed  for  the  separation  of  these  oxides.  To  the  solu- 
tion containing  the  oxide  of  mercury,  (if  it  is  a  suboxide, 
it  must  be  converted  into  the  oxide  by  boiling  with  nitric 
acid,)  hydrochloric  acid  is  added,  and  then  potassa 
nearly  to  neutralization.  Formiate  of  soda  is  added, 
and  the  whole  is  digested  for  several  days  at  a  tempera- 
ture of  from  90°  to  108°,  care  being  taken  that  the 
temperature  last  named  be  not  exceeded.  The  mercury 
falls  as  a  subchloride,  which  is  to  be  collected  upon  a 
weighed  filter.  As  some  mercury  may  escape,  the 
filtrate  is  treated  in  the  same  manner  as  the  original 
solution,  allowed  to  stand  for  twenty-four  hours,  and 
any  precipitate  which  may  fall,  added  to  that  already 
on  the  filter.  The  chloride  is  dried  at  a  very  gentle 
heat,  and  weighed.  The  copper  is  precipitated,  as 
oxide,  from  the  filtered  liquor,  by  hydrate  of  potash. 

SEPARATION  OF  OXIDE  OF  COPPER    FROM    OXIDE   OF    CAD- 
MIUM. 

Carbonate  of  ammonia  in  excess  is  added  to  the  solu- 
tion ;  carbonate  of  cadmium  and  oxide  of  copper,  with 
a  little  oxide  of  cadmium,  remains  in  solution.  If  this 
solution  be  exposed  to  the  air,  the  oxide  of  cadmium  is 
all  deposited,  and  oxide  of  copper  alone  remains  in  solu- 
tion, which  is  precipitated  as  before. 

Cyanide  of  potassium  may  be  employed  by  adding 
this  reagent  till  a  clear  solution  be  obtained.  Sulphu- 
reted  hydrogen  is  passed  through  the  mixture,  sulphuret 
of  copper  remains  in  solution,  and  sulphuret  of  cadmium 
falls.  The  solution  is  boiled,  to  expel  excess  of  sul- 
phureted  hydrogen,  some  cyanide  added,  and  the  hy- 


ANALYSIS  OF  COPPER   ORES.  117 

drocjanic  acid  driven  off  by  evaporation  with  sulphuric 
acid,  or  by  boiling  with  hydrochloric  acid,  nitric  acid 
being  added  from  time  to  time,  as  long  as  any  hydrocy- 
anic acid  is  given  off.  The  copper  is  then  pre'cipitated 
as  oxide. 

SEPARATION  OF  OXIDE  OF  COPPER  FROM  THE  OXIDES  OF 
URANIUM,  NICKEL,  COBALT,  ZINC,  IRON,  AND  MANGA- 
NESE, AND  FROM  THE  EARTHS  AND  ALKALIES. 

The  method  usually  adopted  for  the  separation  of 
oxide  of  copper  from  the  above  named  oxides,  the  sul- 
phurets  of  which  are  soluble  in  dilute  acids,  is  to  preci- 
pitate as  sulphuret  by  a  stream  of  sulphureted  hydrogen 
passed  through  an  acid  solution. 

Some  precautions  must  be  observed  in  order  to  secure 
satisfactory  results.  In  the  first  place,  if  the  solution 
be,  as  it  generally  is,  a  nitro-muriatic  one,  it  must  be 
evaporated  with  repeated  additions  of  hydrochloric  acid, 
to  expel  free  nitric  acid,  for  if  any  of  the  latter  solvent 
remain,  it  will  act  upon  the  recently  precipitated  sul- 
phuret of  copper. 

The  sulphureted  hydrogen  must  be  passed  till  no 
further  precipitate  falls,  and  till  the  solution  smells 
strongly  of  this  reagent.  The  precipitate  must  be 
rapidly  filtered,  and  washed  uninterruptedly,  because  if 
it  remain  any  length  of  time  exposed  to  the  air,  it  ab- 
sorbs oxygen,  and  is  partly  converted  into  'sulphate  of 
copper,  which  passes  through  the  filter,  and  turns  the 
filtrate  brown,  in  consequence  of  a  re-precipitation  of 
the  sulphate  of  copper  by  means  of  the  sulphureted 
hydrogen  it  still  holds  in  solution.  It  is  advisable, 


118  ANALYSIS  OF  COPPER   ORES. 

indeed,  to  wash  it  with  water  charged  with  sulphureted 
hydrogen,  which  decomposes  the  sulphate  on  the  filter 
as  fast  as  it  is  formed.  During  the  whole  process  the 
solution "  and  precipitate  should  smell  strongly  of  this 
gas. 

Various  methods  have  been  adopted  for  the  disposal 
of  this  sulphide.  It  cannot  be  weighed  as  sulphide, 
because  a  portion  of  it  must  be  oxydated  in  drying.  It 
is,  therefore,  to  be  converted  into  oxide.  To  effect  this, 
some  roast  it  in  a  platinum  or  porcelain  crucible,  first  at  a 
low  red  heat,  then  at  a  little  higher  temperature,  finally 
raising  the  whole  to  whiteness,  to  expel  the  last  trace  of 
sulphuric  acid.  This  method  cannot  be  trusted,  because 
we  can  never  be  sure  that  there  is  not  some  undecom- 
posed  basic  sulphate  left  behind,  nor  that  some  suboxide 
has  not  been  formed  during  the  process.  It  is,  there- 
fore, advisable  to  dissolve  it  in  some  hot  aqua  regia,  and 
precipitate  the  oxide  of  copper  with  hydrate  of  potash. 

Some  chemists,  after  having  thoroughly  washed  the 
sulphide  of  copper,  introduce  a  clean  beaker  under  the 
funnel,  perforate  the  bottom  of  the  filter,  and  wash  down 
the  sulphide  with  distilled  water.  The  precipitate  is 
then  treated  as  before  with  aqua  regia. 

Others  allow  the  precipitate  to  dry  till  it  can  be  easily 
separated  from  the  filter.  It  is  then  detached,  and 
treated  again  with  aqua  regia.  The  filter,  which  re- 
tains a  little  sulphide,  is  burned,  and  its  ash,  dissolved 
in  aqua  regia,  added  to  the  solution  of  the  precipitated. 
The  whole  is  then  filtered  and  precipitated. 

It  is  a  bad  plan  to  digest  the  filter  with  the  precipi- 
tate in  nitric  acid  or  aqua  regia,  because  the  action  of 


ANALYSIS  OF  COPPER  ORES.  119 

the  nitric  acid  on  the  paper,  generates  an  organic  com- 
pound which  materially  interferes  with  the  precipitation 
by  solution  of  potash.  When  this  has  heen  done  inad- 
vertently, the  solution  is  to  be  evaporated  to  dryness 
with  sulphuric  acid  in  slight  excess,  the  resulting  sul- 
phate of  copper  dissolved  in  water  and  precipitated  with 
potash. 

It  should  be  remarked  that  this  process,  though  com- 
monly adopted,  is  not  applicable  when  zinc  and  nickel 
are  present,  because  appreciable  quantities  of  these  me- 
tals always  go  down  along  with  the  copper.  To  meet 
this  difficulty,  M.  Flajolot  has  indicated  a  method  of  ac- 
complishing this  by  means  of  hyposulphite  of  soda,  or  of 
sulphurous  acid  solution  of  iodine. 

The  former  reagent  is  employed  in  the  following 
manner :  The  solution  must  contain  neither  hydrochlo- 
ric nor  nitric  acid,  both  of  which  are  expelled  by  evapo- 
ration with  sulphuric  acid.  Water  is  then  added,  and  a 
solution  of  hyposulphite  of  soda  poured  into  the  solution 
of  the  mixed  oxides,  kept  at  the  boiling  point,  till  it  no 
longer  produces  a  black  precipitate.  The  complete 
precipitation  is  known  by  the  subsidence  of  the  subsul- 
phide  of  copper  and  the  absence  of  suspended  sulphur 
in  the  supernatant  liquor.  This  precipitate  is  collected 
on  a  filter,  washed  with  boiling  water,  and  treated  as 
already  described,  to  convert  it  into  oxide  of  copper. 
The  zinc,  nickel,  or  cobalt,  is  precipitated  with  carbo- 
nate of  soda  from  the  nitrate  from  the  subsulphide  of 
copper. 

By  this  method  copper  may  be  separated  from  all 
those  metals  which  are  not  precipitated  from  their  acid 
solutions  by  sulphureted  hydrogen. 


120  ANALYSIS  OF  COPPER    ORES. 

The  second  process  is  conducted  as  follows :  The  sub- 
stance containing  the  copper  is  dissolved  in  nitric  acid, 
the  solution  evaporated  so  as  to  drive  off  the  greater 
part  of  the  excess  of  acids ;  water  is  then  added,  and  if 
antimony  be  present,  tartaric  acid.  Should  a  residue 
remain  after  digestion,  it  is  filtered,  and  to  the  clear 
solution  are  added,  first,  sulphurous  acid,  and  then 
iodine  dissolved  in  sulphurous  acid.  This  last  must  be 
poured  in  in  small  portions,  and  the  operator  should 
stop  as  soon  as  the  precipitate  ceases  to  fall.  The 
liquid  should  be  allowed  to  stand  at  least  twelve  hours 
before  filtering,  and  this  last  operation  must  be  very 
cautiously  conducted,  as  the  iodide  of  copper  has  a  ten- 
dency to  rise  and  run  over  the  edge  of  the  filter. 

The  iodide  thus  obtained  may  be  dried  at  a  steam 
heat,  and  then  weighed ;  or  it  may  be  dissolved  in  aqua 
regia,  like  sulphide  of  copper ;  or  it  may  be  dissolved 
in  ammonia,  exposed  to  the  air  some  hours,  so  as  com- 
pletely to  oxidize  the  product,  and  filtered ;  or,  finally, 
it  may  be  introduced  into  a  matrass,  and  dissolved  in  a 
stream  of  chlorine.  In  whatever  manner  the  solution 
be  effected,  the  copper  is  precipitated  and  weighed  as 
oxide. 

Berthier  separates  oxide  of  copper  from  the  oxides 
under  consideration,  by  boiling  the  solution  with  excess 
of  sulphite  of  ammonia.  Copper  alone  is  precipitated 
as  a  subsulphite. 

A  very  common,  but  altogether  objectionable,  method 
of  separating  copper  from  iron,  is  to  precipitate  the  iron, 
as  sesquioxide,  with  ammonia.  Copper  remains  in  solu- 
tion, and  the  whole  being  thrown  on  the  filter,  the 
precipitate  is  thoroughly  washed,  dried,  ignited,  and 


ANALYSIS   OF  COPPER  ORES.  121 

weighed.  The  copper  is  then  estimated  as  oxide,  in 
the  manner  already  described.  A  notable  proportion 
of  copper  is  lost  by  this  process,  since  it  goes  down 
entangled  with  the  iron,  and  escapes  the  ammoniacal 
solvent.  I  have  repeatedly  tried  it  upon  weighed  mix- 
tures of  pure  copper  and  iron,  and  have  invariably  got 
an  excess  of  the  last  named  metal,  in  spite  of  the  most 
careful  washing.  In  some  instances  this  has  amounted 
to  nearly  two  per  cent. 

The  process  of  precipitating  the  copper,  in  the  metal- 
lic state,  with  iron  wire,  is  quite  applicable  to  its  separa- 
tion from  these  metals,  since  none  of  them  are  thrown 
down  by  iron. 

Hautefeuille  recommends  the  following  process  of 
separating  copper  and  zinc  in  the  analysis  of  alloys 
of  those  metals :  One  gramme  of  the  alloy  is  treated 
with  nitric  acid,  and  ammonia  added  to  precipitate 
any  tin,  lead,  antimony,  or  iron,  that  may  be  pre- 
sent. Acetic  acid  is  now  added  in  excess,  and  a 
sheet  of  lead  suspended  in  the  solution,  the  whole  being 
kept  boiling  for  two  hours,  after  which  time  the  liquid 
will  be  colorless,  the  copper  being  precipitated  as  metal 
upon  the  surface  of  the  lead.  In  adopting  this  plan, 
arsenic  must  first  be  got  rid  of  by  a  known  weight  of 
litharge. 

SEPARATION  OF    GOLD   FROM  COPPER. 

Gold  is  frequently  separated  from  copper  in  the  dry 
way,  by  cupellation,  a  process  which  will  presently  be 
described. 

It  may  be  conveniently  "separated  by  sulphate  of  iron. 
11 


122  ANALYSIS   OF  COPPER  ORES. 

This  salt  ought  to  be  of  a  beryl  green  hue  approaching 
blue ;  should  it  be  yellowish  green,  it  contains  oxide  of 
iron,  which  somewhat  delays  the  determination  of  the 
precious  metal.  The  solution  of  aqua  regia  is  repeat- 
edly evaporated  to  dryness  with  hydrochloric  acid,  till 
all  traces  of  nitric  acid  have  been  expelled ;  the  residue 
dissolved  in  water,  and  solution  of  sulphate  of  iron 
added  to  it  so  long  as  a  precipitate  falls.  The  solution 
of  the  mixed  metals  should  be  kept  decidedly  acid  du- 
ring the  entire  process.  Gold  is  precipitated,  and  cop- 
per remains  in  solution. 

Oxalic  acid  may  be  added  to  the  acid  hydrochloric 
solution  of  the  mixed  metals,  the  same  precautions  being 
observed  in  regard  to  the  expulsion  of  nitric  acid.  A 
slow  evolution  of  carbonic  acid  takes  place  ;  gold  is  pre- 
cipitated, and  copper  remains  in  solution. 

Or,  the  acid  solution  may  be  just  neutralized  with 
soda  or  potash,  and  sulphurous  acid  being  added,  the 
whole  is  boiled,  the  gold  being  precipitated  and  the  cop- 
per remaining  in  solution. 

SEPARATION  OF  COPPER  FROM  ANTIMONY,  ARSENIC,  TIN, 
PLATINUM,  GOLD,  IRIDIUM,  TELLURIUM,  TUNGSTEN, 
VANADIUM,  AND  MOLYBDENUM. 

The  sulphides  of  the  metals  above  enumerated,  being 
all  soluble  in  alkaline  sulphides,  a  simple  process  suffices 
to  separate  them  from  copper.  The  solution  having 
been  carefully  neutralized,  is  precipitated  with  sul- 
phide of  potassium.  The  metals  above  named  all 
remain  in  solution,  while  sulphide  of  copper  goes  down 
mixed  with  the  sulphides  of  metals  the  separation  of 
which  from  copper  we  have  already  studied. 


ANALYSIS   OF  COPPER  ORES.  123 

The  common  method  is  to  precipitate  the  copper  from 
the  acid  solution  with  sulphureted  hydrogen,  and  then 
to  boil  the  mixed  sulphides  with  yellow  sulphide  of 
ammonia,  as  already  described  under  the  head  of  Quali- 
tative Analysis.  The  objection  to  this  process  is,  that 
sulphide  of  copper  not  being  entirely  soluble  in  sulphide 
of  ammonia,  some  of  that  metal  is  lost. 

We  shall  make  a  few  remarks  on  this  subject  under 
the  next  head. 

ASSAY   OF   COPPER. 

The  term  assay  is  applied  both  to  the  dry  and  the 
wet  method  of  determining  the  quantity  of  metal  in  an 
ore  or  an  alloy.  The  classification  of  ores,  however,  is 
generally  based  upon  the  convenience  of  the  dry  assay. 
For  this  purpose,  copper  compounds  are  classified  as 
ores  and  alloys.  The  ores  are  distributed  under  three 
heads. 

I.  Substances  which  are  entirely  free  from  sulphur, 
selenium,  and  arsenic,  and  contain  no  other  metal  but 
iron. 

II.  Substances  which  contain  sulphur  or  selenium, 
but  no  foreign  metal  but  iron. 

III.  Sulphides  which  contain  various  metals. 

For  the  performance  of  the  dry  assay,  certain  arti- 
cles of  laboratory  furniture  are  indispensable.  The 
operator  should  have  a  good  wind  furnace.  One  four- 
teen inches  square  by  twenty-four  deep,  with  a  chimney 
thirty  feet  high,  will  give  heat  enough  for  an  iron  assay. 
A  very  good  size  for  a  copper  furnace  is  nine  inches 
square  by  sixteen  deep.  This  will  give  a  sufficient 


124  ANALYSIS   OF  COPPER  ORES. 

body  of  coal  for  ordinary  purposes.  It  is  well  enough 
to  have  another  furnace  of  the  same  length  and  breadth, 
but  only  six  or  eight  inches  deep,  .with  the  flue  opening 
as  near  as  possible  the  top.  An  iron  plate  covers  the 
furnace,  forming  a  sort  of  table  over  the  flues,  and  the 
upper  openings  are  closed  by  sliding  plates.  The  flue 
ought  to  have  a  chimney  to  regulate  the  draught. 
When  these  conveniences  are  not  to  be  had,  a  copper 
assay  can  be  made  in  a  cylinder  anthracite  stove,  pro- 
vided it  has  a  strong  draught,  or  even  in  a  smith's  forge. 
In  the  latter  case,  however,  great  care  must  be  taken  to 
avoid  too  high  a  heat. 

The  operator  must,  of  course,  have  suitable  tongs, 
pokers,  &c.,  with  iron  rods  flattened  at  the  end,  for  the 
purpose  of  stirring  the  roasting  ore.  The  crucibles 
employed  may  be  either  the  common  Hessian  or  the 
French  of  Beaufaye,  which  last  are  more  durable,  though 
this  is  a  matter  of  no  great  consequence  in  a  copper 
assay. 

He  must  also  be  provided  with  finely  powdered  lime, 
kept  in  a  well-stopped  bottle ;  carbonate  of  soda,  which 
has  been  dried  by  heating  to  low  redness,  also  kept  in 
the  same  way ;  fine  powder  of  charcoal ;  dried  borax 
and  black  flux.  The  latter  is  easily  prepared  by  mixing 
two  parts  of  argol,  the  crude  tartar  of  commerce,  with 
one  of  nitre,  and  igniting  them  with  a  red  hot  iron  rod. 
Some  other  reagents  in  the  dry  way  are  used,  which 
will  be  mentioned  further  on  ;  but  those  just  named  are 
sufficient  for  most  purposes. 

The  best  fuel  for  the  purposes  of  the  assayer  is  coke. 
The  firmest  pieces  are  selected  and  broken  into  pieces 


ANALYSIS   OF  COPPER  ORES.  125 

about  the  size  of  small  egg  coal.  It  is  well  to  have  two 
sizes  of  broken  fuel,  one  large,  for  the  general  heat, 
and  another  smaller,  for  fitting  around  the  crucible.  If 
the  fuel  be  too  small,  the  draught  will  be  obstructed ;  if  it 
be  too  large,  it  will  be  difficult  to  arrange  it  properly 
around  the  crucible.  Charcoal  or  anthracite  may  be 
used  if  the  operator  cannot  get  coke ;  but  the  first  is 
troublesome,  because  it  burns  out  so  rapidly  that  it 
requires  constant  replenishing,  and  the  latter  is  annoy- 
ing, on  account  of  its  propensity  to  split  and  fly. 
Bituminous  coal  is  dirty  and  smoky,  and  its  swelling 
interferes  with  the  operation.  The  crucible  is  some- 
times placed  in  a  hollow  in  the  fire,  but  more  commonly 
it  rests  on  a  support  of  fire-brick,  placed  on  the  grate 
bars,  and  the  fire  is  built  up  around  it.* 

ASSAY  OF  SUBSTANCES  OF  THE  FIRST  CLASS. 

When  the  ores  or  slags  of  this  class  are  tolerably 
rich,  the  assay  is  simple  and  easy.  The  substance  is . 
reduced  to  a  fine  uniform  powder,  by  rubbing  it  up  in  a 
mortar,  and  passing  it  through  a  sieve.  Should  there 
be  much  metallic  copper  present,  it  will  be  very  difficult 
to  pulverize  it,  as  it  will  flatten  out  in  little  sheets 
under  the  pestle.  In  this  case,  it  is  customary  to  sepa- 
rate these  strips,  and  estimate  the  copper  in  them  sepa- 
rately. It  is  then  a  simple  calculation  to  apportion  the 
per  centage.  If,  however,  the  assay  is  to  be  made  of 
the  entire  mass  powdered,  they  must  be  thrown  in. 

The  fine  powder  is  now  to  be  mixed  with  three  times 

*  For  further  information  on  this  subject,  see  my  work  on  Dental 
Chemistry  and  Metallurgy. 

11* 


126  ANALYSIS   OF  COPPER  ORES. 

its  weight  of  black  flux,  in  a  porcelain  mortar,  and 
poured  into  a  crucible.  The  mortar  is  then  to  be 
rinsed  out  with  black  flux,  which  is  to  be  added  to  the 
mixture  already  in  the  crucible,  and  then  covered  with 
a  thin  layer  of  the  same  flux,  unmixed  with  ore.  As 
the  fusion  of  these  ingredients  will  cause  the  mass  to 
swell  and  bubble,  care  must  be  taken  to  select  a  cru- 
cible so  large  that  it  will  be  only  half  filled  with  the 
mixture. 

The  whole  is  then  introduced  into  a  furnace,  which 
has  been  previously  heated.  The  heat  is  gradually 
raised  to  bright  redness.  At  this  point,  the  mass  be- 
comes pasty,  and  begins  to  rise  and  fall,  little  puffs  of 
vapor  breaking  through  the  imperfectly  fused  materials. 
Each  jet  of  vapor  burns  with  a  violet  flame,  showing 
the  combustion  of  the  reduced  and  volatilized  potassium 
of  the  black  flux.  When  a  mixture  of  carbonate  of 
soda  and  powdered  charcoal  is  substituted  for  this  re- 
agent, the  flames  are  yellow.  In  about  fifteen  or  twenty 
minutes  the  bubbling  ceases,  and  the  contents  of  the 
crucible  sink  down  in  tranquil  fusion  to  the  bottom  of 
the  pot.  The  surface  of  the  flux  is  smooth,  and  marked 
with  lines  radiating  from  the  centre  to  the  circumfe- 
rence. An  earthen  cover  is  now  put  upon  the  crucible, 
and  the  heat  is  pushed  nearly  to  whiteness,  and  kept  at 
that  for  about  ten  minutes.  At  the  end  of  that  time 
it  is  withdrawn,  and  tapped  gently  on  some  hard  sub- 
stance, to  cause  the  small  globules  of  molten  metal 
diffused  through  the  slag  to  settle  to  the  bottom.  If 
the  fusion  has  been  carried  far  enough,  the  slag  will 
have  a  smooth,  shining  surface,  depressed  in  the  centre. 


ANALYSIS   OF  COPPER  ORES.  127 

When  the  crucible  is  cold  enough,  it  is  broken,  and  the 
copper  extracted. 

If  the  operation  has  been  successful,  the  button  of 
copper  has  a  clean,  polished  surface,  and  does  not  ad- 
here to  the  crucible.  Should  it  be  marked  by  little 
depressions,  it  is  an  indication  that  the  heat  has  been 
too  high,  and  that  some  copper  has  been  volatilized. 
The  quality  of  the  metal  is  tested  by  hammering  it  out 
upon  a  smooth  anvil.  If  it  is  soft,  yields  easily,  and 
flattens  down  without  breaking  at  the  edges,  it  is  com- 
monly regarded  as  pure  copper,  for  iron  usually  renders 
it  brittle.  This  is,  however,  by  no  means  a  universally 
reliable  test.  There  are  alloys  of  iron  and  copper 
which  are  malleable,  and  I  have  seen  an  assay  button, 
containing  33  per  cent,  of  iron,  flatten  out  unexception- 
ably  under  the  hammer.  The  proper  plan,  therefore, 
is  to  dissolve  the  button  in  aqua  regia,  and  test  for 
iron. 

The  quantity  of  ore  to  be  employed  for  this  purpose, 
varies  with  its  richness.  Of  average  ores,  200  grains 
are  sufficient ;  while  for  poorer  ores,  400  grains  should 
be  taken. 

It  sometimes  happens  that  these  ores  of  the  first  class 
are  contaminated  with  some  sulphur,  in  which  case  the 
copper  button  will  be  surrounded  by  a  steel-gray  invest- 
ment of  sulphide  of  copper.  When  this  is  the  case,  the 
ore  must  be  treated  in  the  manner  presently  to  be  de- 
scribed, under  the  head  of  Ores  of  the  Second  Class. 

Slags  are  commonly  assayed  in  this  manner ;  but 
when  they  are  poor,  containing  only  two  or  three  per 
cent,  of  metal,  all  the  copper  is  not  readily  obtained, 


128  ANALYSIS  OF  COPPER  ORES. 

since  the  viscidity  of  the  slag  retains  some  of  it,  and 
other  portions  of  it  enter  into  chemical  combinations 
with  the  various  ingredients.  Under  these  circumstan- 
ces, it  will  be  well  to  dissolve  the  slag,  if  soluble,  in 
acids,  and  estimate  the  capper  by  the  methods  already 
described.  It  often  happens,  however,  that  slag  is  a 
definite  silicate  which  will  not  dissolve  in  acid.  In 
these  cases,  a  moderate  quantity — 100  or  200  grains — 
is  fused  in  a  platinum  or  smooth  porcelain  crucible  with 
twice  its  weight  of  dry  carbonate  of  soda.  The  whole 
crucible  is  introduced  into  a  beaker,  containing  distilled 
water,  and  digested  at  a  moderate  heat  till  the  softened 
mass  swells  and  separates  readily  from  the  crucible.  It 
is  then  treated  with  aqua  regia,  in  a  flask  or  matrass, 
the  solution  transferred  to  a  porcelain  capsule,  evapora- 
ted to  dryness,  moistened  with  hydrochloric  acid,  re- 
dissolved  in  water,  and  the  copper  estimated  in  the 
manner  already  described. 

If,  however,  it  be  desired  to  determine  it  in  the  dry 
way,  the  substance  may  be  fused  at  the  high  heat  of  an 
iron  assay,  the  operation  being  considerably  prolonged. 
When  the  crucible  is  removed  and  broken,  a  button, 
containing  a  large  amount  of  iron,  will  be  found.  This 
is  to  be  analyzed,  as  already  described,  in  the  humid 
way. 

A  better  plan  than  this,  is  to  sulphurate  the  poor  slag 
or  ore,  as  the  globules  of  sulphuret  are  larger  than 
those  of  metallic  copper,  and  fall  more  readily  through 
the  melted  slag.  The  metal  is  then  obtained  in  the 
form  of  a  flattened  button  of  sulphide,  the  further  assay 
of  which  is  conducted  as  shall  be  described  in  the  next 


ANALYSIS   OF  COPPER  ORES.  129 

section.     This   process,  though    tedious,    yields   better 
results  than  any  other  dry  process  for  poor  ores. 


ASSAY  OF  SUBSTANCES  OF  THE  SECOND  CLASS. 

Ores  of  this  class  contain  sulphur,  and  sometimes 
selenium,  are  generally  sulphides  or  sulphates,  and 
are  assayed  either  for  regulus  or  matt,  or  for  cop- 
per. 

SULPHATES.  With  a  reducing  flux,  the  sulphates 
yield  copper  and  a  slag  containing  a  double  sulphide  of 
copper  and  the  alkaline  metal  of  the  flux.  The  more 
of  the  latter  is  employed,  the  less  metal  and  the  more 
sulphureted  slag  is  obtained ;  but  if  it  be  only  used  in 
sufficient  quantity  to  reduce  the  copper,  the  metal  sub- 
sides pure,  and  a  slag  remains  containing  only  sul- 
phate. 

"  Thus,  it  has  been  ascertained  that  the  neutral  anhy- 
drous sulphate  of  copper  gives,  firstly,  27  per  cent,  of 
copper,  with  three  parts  of  black  flux,  (about  two-thirds 
only  of  that  which  it  contains,)  and  a  black  crystalline 
slag,  containing  much  sulphur.  Secondly,  with  two 
parts  of  the  same  flux,  37  per  cent,  of  copper  and  a 
clean  gray  slag,  containing  very  little  sulphur.  When 
but  one  part  of  black  flux  is  employed,  there  is  not  a 
sufficiency  of  carbon  to  reduce  the  whole  of  the  oxide, 
and  only  about  12  or  14  per  cent,  of  metallic  copper  is 
produced,  which  is  enveloped  in  a  red,  vitreous,  opaque 
slag,  composed  of  protoxide  of  copper  and  alkali,  and 
above  which  is  a  layer  of  fused  sulphate  of  potash, 
which  is  crystalline  and  colorless. 


130  ANALYSIS  OF  COPPER  ORES. 

"  It  may  thus  be  seen  that  in  order  to  extract  the 
whole  of  the  copper  from  a  sulphate  in  this  manner, 
that  the  proportion  of  reducing  flux  which  will  give 
the  maximum  result,  and  which  will  also  produce  a  slag 
containing  but  little  sulphur,  must  be  arrived  at  by 
guess-work. 

"  The  sulphates  of  copper,  however,  are  completely 
decomposed  by  heat ;  and  the  easiest  and  best  method 
of  assaying  them,  is  to  expose  them  to  a  white  heat  in 
a  platinum  crucible  till  nothing  more  is  given  off.  The 
residue  is  oxide,  which  can  be  fused  with  three  parts  of 
black  flux,  when  all  the  copper  contained  in  it  is  exactly 
and  readily  separated  in  the  metallic  state. 

"  The  compounds  of  oxide  of  copper  with  sulphuric 
acid  may  be  assayed  by  fusion  in  an  earthen  crucible 
with  from  one  to  two  parts  of  carbonate  of  soda ;  the 
fused  matter  must  be  poured  into  an  ingot-mould,  pul- 
verized, and  re-fused  in  the  same  crucible,  after  mixture 
with  its  own  weight  of  black  flux.  By  fusion  with  car- 
bonate of  soda,  the  sulphate  of  copper  is  decomposed, 
and  sulphate  of  soda  and  a  compound  of  the  oxide  of 
copper  and  alkali  formed,  which  is  afterwards  com- 
pletely reduced  by  black  flux,  without  the  possibility  of 
the  formation  of  a  sulphuret  of  copper."* 

The  sulphates  of  copper,  however,  being  soluble  in 
water,  are  more  easily  analyzed  by  the  humid  process. 
The  substance  is  dissolved  in  hot  water,  filtered,  well 
washed,  acidulated  with  hydrochloric  acid,  and  the  cop- 
per precipitated  from  it  by  metallic  iron. 

*  Mitchell's  Manual  of  Assaying. 


ANALYSIS   OF  COPPER  ORES.  131 

SULPHIDES.  Fusion  for  Regulus  or  Matt.  This  is 
a  simple  process,  and  easily  performed  by  the  merest  tyro. 
All  that  is  necessary  is  to  mix  the  ore  with  its  own 
weight  of  glass  of  borax,  to  introduce  it  into  a  crucible, 
and  heat  it  to  full  redness.  The  gangue  or  vein-stone 
enters  readily  into  fusion  with  the  borax,  and  the  sul- 
phide or  regulus  subsides.  Care  must  be  taken  in 
separating  this  from  the  crucible,  as  it  is  exceedingly 
brittle,  and  apt  to  stick  to  the  sides  and  bottom.  To 
obviate  this,  Berthier  lined  his  crucibles  with  charcoal, 
which  allows  the  button  to  be  readily  detached,  when  the 
crucible  is  broken.  Phillips  recommends  the  use  of  a 
common  crucible,  but  pours  the  whole  fused  mass  into 
an  iron  mould,  of  an  elliptical  form,  from  which  the 
regulus  is  easily  separated,  by  turning  the  mould  over 
when  cold,  and  giving  it  a  few  taps  upon  some  hard 
body. 

During  this  process,  some  sulphur  is  sublimed,  whence 
it  happens  that  the  regulus  contains  less  sulphur  than 
the  ore.  It  is  manifest,  therefore,  that  the  proportion 
of  vein-stone  cannot  be  determined  from  the  loss  expe- 
rienced in  this  fusion. 

If  the  operator  wishes  to  imitate  the  furnace  processes, 
by  using  the  fluxes  employed  in  smelting  on  a  large  scale, 
such  as  quartz,  baryta,  lime,  &c.,  the  crucible  must  be 
lined  and  the  heat  that  of  an  iron  assay. 

Assay  for  Copper.  In  order  to  estimate  copper  in 
the  dry  way  in  this  class  of  ores,  it  is  necessary  first  to 
roast  them  so  thoroughly  as  to  expel  every  trace  of  sul- 
phur. In  order  to  accomplish  this,  it  is  necessary  first 
to  reduce  the  ore  to  the  finest  possible  powder,  to  intro- 


132  ANALYSIS   OF  COPPER  ORES. 

duce  it  into  a  crucible,  and  place  the  whole  in  a  furnace, 
which  should  be  at  a  low  red  heat.  The  crucible  is  laid 
slanting  in  the  fire,  the  damper  closed,  and" the  ore  stir- 
red assiduously  with  an  iron  rod,  so  as  continually  to 
expose  fresh  surfaces  to  the  air.  It  is  essential  that  at 
this  period  the  heat  should  be  low,  test  the  sulphuret 
should  fuse  or  at  least  agglutinate,  a  circumstance 
which  would  necessarily  interfere  with  the  oxydation. 
Blue  flames  of  sulphur  will  be  seen  to  play  over  the  sur- 
face of  the  roasting  mass,  but  they  gradually  give  place 
to  white  fumes  of  sulphurous  acid.  These,  in  their  turn, 
disappear,  and  the  heat  is  slowly  raised,  the  ore  being 
constantly  stirred.  The  operator,  from  time  to  time, 
holds  a  glass  rod  moistened  with  ammonia,  over  the  cru- 
cible, to  determine  by  the  fumes,  whether  sulphurous 
acid  continues  to  be  given  off.  The  heat  is  pushed  now 
and  then  to  full  redness,  which  expels  the  sulphurous 
acid  formed  by  the  mutual  reaction  of  the  sulphides  and 
sulphates.  When  the  fumes  on  the  rod  dipped  in  am- 
monia are  no  longer  visible,  the  heat  is  raised  to  white- 
ness in  order  to  decompose  the  sulphates  by  driving  off 
their  sulphuric  acid. 

Mitchell  objects  to  this  process  of  roasting  as  ineffi- 
cient, since  some  of  the  sulphates  remain  undecomposed 
even  at  this  elevated  temperature.  To  meet  this  diffi- 
culty, he  proposes  to  stir  in  with  the  roasting  ore,  at 
full  redness,  some  carbonate  of  ammonia  in  small  por- 
tions, so  that  a  double  decomposition  may  take  place, 
and  the  sulphuric  acid  be  all  driven  off  as  sulphate  of  am- 
monia. In  practice,  however,  this  process  is  objectiona- 
ble. It  matters  not  how  cautiously  the  carbonate  of 


ANALYSIS   OF  COPPER  ORES.  133 

ammonia  be  added,  it  is  dispersed  with  a  kind  of  explo- 
sion which  inevitably  causes  a  loss  of  some  of  the  finely 
powdered  ore.  When  the  crucible  is  allowed  to  cool  be- 
fore the  addition  of  this  volatile  salt,  and  then  reheated, 
this  objection  does  not  hold.  Mitchell  pulverized  his 
carbonate  of  ammonia  and  added  it  in  the  proportion  of 
one-tenth  the  entire  amount  of  ore.*  If,  however,  the 
assayer  take  care  to  heat  the  ore  to  whiteness,  he  may 
be  certain  that  all  the  sulphuric  acid  will  be  expelled. 

The  reduction  of  the  roasted  ore  is  commonly  effected 
by  mixing  it  with  three  or  four  times  its  weight  of  black 
flux,  introducing  it  into  the  same  crucible  in  which  the 
roasting  was  effected,  covering  it  with  about  half  an  inch 
of  glass  of  borax,  and  heating  it  in  a  wind  furnace  for 
about  twenty  minutes,  in  the  manner  described  under  the 
last  head. 

If  the  gangue  be  silicious  and  aluminous,  the  fusion 
is  facilitated  by  the  addition  of  lime  to  the  flux,  on  the 
well-known  general  principle  that  a  mixture  of  several 
earths  is  more  fusible  than  a  single  one.  If  the  usual 
quantity  of  ore  (200  grains,)  has  been  selected  for  an 
assay,  it  may  be  thoroughly  mixed  in  a  mortar  with  50 
grains  of  lime,  300  of  dry  carbonate  of  soda  (i.  e.  car- 
bonate of  soda,  recently  heated  to  redness,)  and  from  20 
to  40  grains  of  charcoal,  according  to  the  richness  of 
the  ore.  Some  assayers  make  it  into  a  paste  with  oil 
and  pack  it  in  the  crucible.  The  whole  is  now  intro- 
duced into  the  fire  and  kept  at  a  dull  red  heat  for  about 
fifteen  minutes,  or  until  the  mass  has  ceased  to  swell 

*  Should  the  arsenic  be  present,  it  is  advisable  to  mix  the  ore  with 
charcoal.  Some  make  it  into  a  paste  with  sawdust  and  oil. 

12 


134  ANALYSIS   OF  COPPER  ORES. 

and  bubble.  It  is  then  covered  with  an  earthen  lid  and 
heated  to  a  full  red  approaching  whiteness,  for  about  the 
same  length  of  time.  It  is  not  absolutely  necessary  to 
cover  the  crucible,  but  it  is  better  to  do  so,  as  some  bits 
of  coal  may  get  in,  and  cause  a  loss  of  copper  which 
may  adhere  to  their  rough,  irregular  surface. 

The  crucible  having  cooled,  is  broken  and  the  metallic 
button  removed.  Any  adhering  particles  of  slag  are 
easily  removed  by  a  few  gentle  taps  of  the  hammer. 
The  surface  of  the  button  is  now  examined.  If  it  is 
clean  and  bright,  it  may  be  inferred  that  the  operation 
has  been  properly  conducted.  If,  however,  it  be  envel- 
oped in  a  coating  of  gray  brittle  regulus,  the  assayer 
may  know  that  his  roasting  has  been  imperfectly  per- 
formed and  that  all  the  sulphur  has  not  been  expelled. 
The  whole  operation  must  then  be  repeated.  It  is  al- 
ways advisable  to  prepare  two  crucibles  in  the  same  man- 
ner, and  to  carry  on  the  operation  upon  two  samples  of 
ore  at  the  same  time. 

Various  processes  have  been  suggested,  in  order  to 
avoid  the  trouble  and  delay  of  roasting.  Mr.  Maughan 
suggested  an  ignition  in  oxygen.  He  placed  the  sub- 
stance in  a  porcelain  tray  which  was  introduced  into  a 
tube  heated  to  redness,  while  a  stream  of  oxygen  gas 
was  passed  over  it.  The  roasting  was  in  this  manner 
very  rapidly  accomplished,  but  the  difficulty  of  decom- 
posing the  sulphates  was  not  overcome. 

"  With  nitre  all  the  copper  can  be  extracted,  (from 
the  sulphuret,)  but  with  difficulty,  and  finding  by  repeat- 
ed experiments,  the  quantity  which  produces  the  maxi- 
mum result.  Sulphuret  of  copper  fused  with  a  mixture 


ANALYSIS   OF  COPPER  ORES.  135 

of  an  alkaline  carbonate  and  metallic  iron,  allows  a  cer- 
tain quantity  of  copper  to  be  set  free  ;  but  this  quan- 
tity never  surpasses  three-fourths  of  that  contained. 
This  maximum  is  obtained  by  using  four  parts  of  car- 
bonate of  soda,  and  thirty  or  forty  per  cent,  of  iron  fil- 
ings. The  slag  is  black  and  homogenous. 

"  Copper  pyrites  is  decomposed  by  the  alkaline  car- 
bonates, but  without  the  production  of  metallic  copper. 
A  black  crystalline  homogeneous  slag  is  formed,  which 
contains  an  alkaline  sulphuret,  a  sulphuret  of  iron,  sul- 
phuret  of  copper  and  oxide  of  iron. 

"  With  black  flux  a  very  fluid  homogeneous  crystal- 
line slag  is  produced,  the  color  of  which  is  black  with  a 
metallic  lustre,  and  in  which  not  the  smallest  trace  of 
metallic  copper  can  be  distinguished.  The  result  is  the 
same  as  the  addition  of  iron,  which  is  perfectly  inert, 
and  remains  disseminated  in  the  slag. 

"  Copper  pyrites  is  readily  attacked  by  nitre,  and 
either  copper  or  sulphuret  of  copper  can  be  separated 
from  it  by  means  of  this  reagent.  But  in  order  to  ar- 
rive at  this  result,  it  is  necessary  to  guess  the  quantity 
of  nitre ;  so  that  it  is  evidently  not  a  good  method  of 
assay. 

"  It  is  necessary,  in  order  that  the  slag  be  fluid,  to 
add  a  little  borax  or  an  alkaline  carbonate  ;  so  that  the 
reduced  metal  may  collect  into  one  button.  With  one 
part  of  nitre,  two  of  carbonate  of  soda  and  one  of  bo- 
rax, pure  copper  pyrites  gives  from  36  to  46  per  cent, 
of  sulphuret ;  with  double  that  quantity  of  nitre  it  gives 
thirty  per  cent,  of  metallic  copper." 

The  above  account  of  the  behaviour  of  sulphureted 


136  ANALYSIS   OF  COPPER  ORES. 

copper  ores,  with  different  reagents,  taken  from  Mitch- 
ell's Manual,  throws  light  upon  the  various  processes 
adopted.  The  success  of  the  nitre  assay  depends  upon 
its  oxydating  the  sulphur  in  the  mixed  sulphides  of  the 
ore,  forming  sulphuric  acid  which  combines  with  the 
potash.  If  the  exact  quantity  of  nitre,  necessary  for 
this  oxydation,  be  hit  upon,  the  maximum  quantity  of 
metallic  copper  is  obtained. 

Mr.  Lewis  Thompson  has  suggested  a  nitre  process  by 
which  he  proposes  to  get  rid  of  the  guesswork  of  the 
common  fusion  with  nitre.  He  heats  the  finely  powder- 
ed ore  in  a  crucible  to  redness,  and  throws  upon  it  ex- 
cess of  nitre.  Powdered  charcoal  is  then  added  so  long 
as  any  deflagration  takes  place,  and  the  heat  is  pushed 
to  bright  redness  for  a  quarter  of  an  hour. 

The  process  is  an  imperfect  one,  on  account  of  the 
continued  presence  of  the  sulphur.  I  have  repeatedly 
tried  it  with  all  possible  care,  but  have  never  been  able 
to  obtain  satisfactory  results.  Two  crucibles  placed  side 
by  side  in  the  same  fire,  and  treated  as  nearly  as  possible 
in  the  same  manner,  have  often  given  me  different  quan- 
tities of  copper  with  this  process. 

It  occurred  to  me  to  try  cyanide  of  potassium  as  a 
desulphurating  agent,  since  it  is  so  efficient  in  reductions 
before  the  blow-pipe.  My  plan  was  to  fuse  a  small  quan- 
tity of  cyanide  in  the  crucible  and  when  it  was  liquid, 
to  add  to  it  the  finely  powdered  ore.  A  pasty  mass  re- 
sulted which  when  heated  to  redness  swelled  a  good  deal. 
Some  more  cyanide  was  then  thrown  in,  as  long  as  effer- 
vescence took  place,  and  glass  of  borax  placed  on  top. 
The  heat  was  then  pushed  and  the  rest  of  the  process 


ANALYSIS   OF  COPPER  ORES.  137 

conducted  as  before.  I  have  obtained  very  good  results 
in  this  way,  but  often,  without  apparent  cause,  I  have 
failed. 

At  this  point,  I  may  remark  that  the  dry  assay  can- 
not be  relied  on  as  giving  a  satisfactory  determination 
of  the  copper  contained  in  the  ore,  because,  no  matter 
how  carefully  the  process  may  have  been  conducted,  we 
can  never  be  certain  that  the  button  contains  copper 
only.  It  is  valuable,  however,  as  an  indication  of  the 
manner  in  which  the  ore  will  behave  in  the  furnaces,  the 
proportionate  yield  of  metal  which  may  be  expected,  the 
nature  of  the  slag,  and  a  variety  of  similar  matters 
which  will  readily  occur  to  the  mind  of  the  practical  man. 

Sulphureted  ores  are  commonly  dissolved  in  aqua  re- 
gia,  as  already  described.  Mr.  Lewis  Thompson  uses 
chlorate  of  potash  instead  of  nitric  acid  as  an  oxydizing 
agent.  He  pours  upon  100  grains  of  the  finely  powder- 
ed ore  concentrated  hydrochloric  acid,  adds  chlorate  of 
potash  in  small  portions,  stirring  all  the  while  with  a 
glass  rod,  until  all  action  ceases.  Should  the  residue  be 
white,  the  operation  may  be  regarded  as  completed ; 
should  it  still  remain  dark,  it  is  placed  upon  a  sand-bath, 
and  heated,  additions  of  chlorate  of  potash  being  made 
from  time  to  time,  till  all  action  has  ceased.  Should 
the  residue  still  continue  dark,  it  is  to  be  roasted,  and 
then  treated  in  the  same  way  again.  The  resulting  so- 
lutions are  mixed  and  precipitated  with  metallic  iron. 

It  is  necessary  to  conduct  this  operation  under  a  hood, 
with  a  strong  draught,  or  dangerous  results  may  follow 
from  the  stifling  vapors  of  euchloine  which  are  abundant- 
ly evolved. 

12* 


138  ANALYSIS   OF  COPPER  ORES. 

Rivot's  process  may  be  adopted,  when  zinc  in  the  form 
of  sulphide,  is  not  present.  The  ore  having  been  re- 
duced to  an  impalpable  powder,  (by  porphyrization,  if 
necessary,)  is  warmed  with  an  alkaline  liquor,  and  a 
stream  of  chlorine  gas  is  passed  through  the  whole.  The 
copper  and  the  other  metals  remain  at  the  bottom  as 
oxides,  and  the  sulphur,  arsenic  and  antimony  are  con- 
verted into  acids  which  combine  with  the  alkali  to  form 
salts. 

The  dry  process  above  described  may  be  performed 
directly  upon  the  ores  themselves  when  they  are  rich, 
but  when  they  contain  only  8  or  10  per  cent.,  it  is  bet- 
ter to  run  them  down  first  as  regulus  and  then  apply  the 
process  of  roasting  and  fusion  to  that.  If  there  is  much 
earthy  matter  present,  it  interferes  with  the  roasting, 
both  by  shielding  portions  of  the  ore  from  the  oxydating 
influence  of  the  air,  and  by  furnishing  bases  with  which 
the  sulphur  and  newly  formed  sulphuric  acid  may  com- 
bine. In  the  subsequent  fusion  also,  they  have  a  ten- 
dency to  stiffen  the  slag  and  prevent  the  descent  of  the 
globules  of  metal.  It  is,  therefore,  better  in  these  cases 
to  adopt  the  fusion  for  regulus,  as  that  enables  us  to  ob- 
tain all  the  metal  free  from  gangue,  and  the  resulting 
sulphide  can  then  be  treated  like  a  rich  ore. 

ASSAY  OF  ORES  OF  THE  THIRD  CLASS. 

Ores  of  this  kind  require  roasting,  but  it  must  be  con- 
ducted with  more  care  than  the  same  process  employed 
upon  a  simple  sulphide,  because  they  are  far  more  fusi- 
ble than  the  substances  belonging  to  the  last  class.  The 
metal  obtained  from  the  calcined  ore  requires  a  further 


ANALYSIS   OF  COPPER  ORES.  139 

operation,  to  be  described  under  the  next  head,  because 
it  is  a  true  alloy. 

When  the  ore  contains  lead,  especial  care  is  necessary 
in  roasting,  as  it  so  greatly  increases  the  fusibility,  that 
it  is  extremely  difficult  to  expel  all  the  arsenic  and  sul- 
phur, without  agglutinating  the  mass.  It  is  better,  in- 
deed, in  all  cases,  to  obtain  a  regulus  first  and  roast  that, 
as  the  loss  of  sulphur  and  arsenic,  during  the  process  of 
fusion,  renders  the  subsequent  roasting  more  easy,  by 
rendering  the  matt  less  fusible. 

In  an  arsenide  of  copper,  the  first  results  of  roast- 
ing are  volatilization  of  a  portion  of  arsenic  and  the  for- 
mation of  oxide  and  arseniate  of  copper  and  metallic 
copper.  The  arseniates  and  arsenides  react  on  each 
other  at  a  high  heat,  and  arsenious  acid  is  formed  and 
vaporized.  After  the  whole  of  the  arsenide  has  been 
decomposed,  there  still  remains  behind  some  arsenic,  in 
the  form  of  arseniate  of  copper,  which  cannot  be  vola- 
tilized at  a  roasting  heat.  This  is  decomposed  by  add- 
ing finely  powdered  charcoal  and  heating  to  bright  red- 
ness. The  arseniates  are  reduced  with  the  formation  of 
arsenious  acid  which  is  expelled.  In  spite,  however,  of 
all  this  care,  some  arsenic  will  contaminate  the  button 
obtained  in  the  subsequent  fusion. 

ASSAY  OF  SUBSTANCES  OF  THE  FOURTH  CLASS. 

Alloys  containing  more  oxydizable  metals  than  copper 
are  purified  by  a  process  called  refining,  which  is  in 
reality,  a  cupellation  performed  on  copper. 

For  this  purpose  the  operator  must  have  a  cupelling 
or  assay  furnace,  with  a  strong  draught,  some  cupels 
and  tongs  of  a  suitable  construction.  The  furnace 


140  ANALYSIS   OF  COPPER  ORES. 

should  have  a  strong  draught,  and  be  provided  with  a 
muffle  in  which  the  substance  in  the  cupels  is  to  be  heat- 
ed. The  cupels  are  made  of  bone  ash,  and  resemble 
little  saucers  with  a  flat  bottom.  For  fuller  information 
on  the  construction  and  management  of  the  furnace  and 
cupels,  the  reader  is  referred  to  the  author's  work  on 
Dental  Chemistry  and  Metallurgy. 

The  cupel  having  been  introduced  into  the  muffle  and 
the  whole  being  brought  to  a  red  heat,  the  button  of 
copper  is  dropped  into  the  cupel  from  a  pair  of  tongs, 
when  the  muffle  is  closed  to  exclude  the  air  and  raise  the 
temperature  to  the  fusion  point  of  copper.  After  the 
melting  of  the  button,  the  muffle  door  is  opened,  and  a 
little  pure  lead  added  to  the  alloy.  Oxydation  of  the 
lead  and  the  combined  metals  now  begins  ;  the  button  is 
agitated  with  a  rapid  rotary  motion,  and  covered  with 
an  iridescent  pellicle  of  oxide,  which  continually  flows 
off  and  is  absorbed  by  the  cupel.  When  the  process 
is  about  to  terminate,  the  motion  becomes  more  rapid 
and  the  colors  of  the  pellicle  brighten,  till  the  button 
becomes  suddenly  solid,  when  the  coating  disappears  en- 
tirely and  the  movement  of  the  button  ceases.  This  is 
called  brightening  or  fulguration. 

The  cupel  is  now  immediately  removed.  The  button 
is  covered  with  a  fine  crust  of  protoxide  of  copper  which 
is  not  easily  detached  if  allowed  to  cool  slowly,  but 
plunged  while  still  hot  into  water,  the  oxide  can  be 
beaten  off  with  a  hammer.  It  is  usually  recommended 
to  cover  the  button  with  about  7  per  cent,  of  its  weight 
of  pure  fused  borax,  finely  powdered.  The  berate  of 
copper  thus  formed,  is  very  brittle  and  only  slightly  ad- 
herent to  the  metal,  being  easily  detached  by  a  single 


ANALYSIS   OF  COPPER  ORES.  141 

blow  of  the  hammer.  If  the  red  hot  button  be  plunged 
into  a  weak  solution  of  phosphate  of  soda,  the  same  re- 
sults follow.  The  purity  of  the  metal  is  known  by  its 
fine  red  color  and  its  malleability. 

It  must  be  observed,  however,  that  this  method  is  not 
rigorously  exact,  because  some  copper  is  oxydated  and 
sinks  into  the  cupel  along  with  the  lead  and  other  me- 
tals, and  another  portion  is  removed  with  the  coating  of 
oxide  or  borate  of  copper  taken  off  from  the  refined 
button. 

It  is  manifest,  furthermore,  that  two  cases  may  occur ; 
the  copper  alloy  may  not  contain  lead,  or  it  may  be 
mixed  with  that  metal.  In  the  first  case,  a  tenth  part 
of  lead  is  added  till  the  copper  be  pure.  To  determine 
the  true  per  centage  of  copper,  Berthier  recommends 
that  one-eleventh  of  the  weight  of  all  the  oxydizable  me- 
tals including  the  lead  added,  and  one-tenth  of  the 
weight  of  the  borax  thrown  on  the  hot  button  should  be 
added  to  that  of  the.  assay  button  obtained.  It  is  man- 
ifest, that  however  near  this  estimate  may  be  to  the 
truth,  and  however  well  it  may  answer  for  practical  pur- 
poses, it  has  no  claim  to  be  considered  scientifically  ex- 
act, because  the  loss  depends  not  only  upon  the  nature 
of  the  oxydizable  metals  present,  but  also  upon  the  heat 
to  which  the  button  has  been  subjected. 

In  the  second  case,  or  when  the  copper  alloy  contains 
lead,  that  metal  may  exist  in  three  different  conditions  ; 
there  may  be  either  too  little  for  the  purposes  of  the  re- 
finer, or  just  enough,  or  too  much.  When  there  is  too 
little,  lead  must  be  added  by  tenths  till  the  button  is 
pure.  When  there  is  just  enough,  there  is  of  course, 
nothing  to  be  done  but  to  proceed  with  the  cupellation. 


142  ANALYSIS  OF  COPPER  ORES. 

When  there  is  too  much,  a  weighed  quantity  of  pure 
copper  must  be  added,  and  the  usual  allowances  made  in 
estimating  the  button. 

This  process  may  be  conducted  without  the  inconveni- 
ence of  these  numerous  suppositions,  by  operating  at 
once  upon  two  samfples,  one  of  pure  copper,  the  other  of 
the  alloy  to  be  examined.  For  this  purpose,  two  cupels 
are  placed  side  by  side  in  the  same  muffle,  and  when 
heated  sufficiently,  4  parts  of  pure  lead  are  introduced 
into  each.  As  soon  as  the  metal  is  melted,  1  part  of 
pure  copper  is  introduced  into  one,  and  1  part  of  the 
alloy  under  examination  into  the  other. 

The  refining  is  conducted  in  the  usual  manner,  and 
when  the  resulting  buttons  are  weighed,  it  will  be  found 
that  that  obtained  from  the  pure  copper  is  the  heavier. 
By  adding  the  loss  of  the  fine  copper  to  the  weight  of 
the  button  refined  from  the  alloy,  the  quantity  of  pure 
copper  contained  in  the  last  is  determined,  since  we 
have  every  reason  to  suppose  that  the  loss  of  copper  in 
both  assays  is  precisely  the  same. 

In  operating  upon  cupriferous  leads,  1  part  of  pure 
copper  is  treated  with  4  parts  of  pure  lead  in  the  cupel, 
and  with  4  parts  of  the  cupriferous  lead  in  the  other. 
The  second  operation  gives  more  copper  than  the  former, 
and  the  difference  is  the  proportion  of  copper  in  the  cu- 
priferous lead. 

The  advantage  of  this  method  is  that  it  furnishes  good 
data  whereupon  to  compute  the  probable  result  of  me- 
tallurgic  operations  in  such  alloys,  on  the  great  scale. 
The  process  is,  however,  not  applicable  to  alloys  con- 
taining much  zinc  or  tin.  Indeed,  in  all  cases,  the  hu- 
mid analysis  furnishes  by  far  the  most  exact  results. 


CHAPTER  III. 

MINES    AND    MINING. 

IT  is  necessary,  in  order  to  understand  the  character 
of  mineral  deposits,  to  have  some  distinct  ideas  of  the 
general  principles  of  geology.  We  shall,  therefore,  re- 
call to  our  readers'  recollection  a  few  of  the  simpler 
facts  of  that  science,  before  proceeding  to  give  an  ac- 
count of  mines  or  mining  operations. 

The  earth,  upon  which  we  live,  is  generally  believed 
to  be  a  mass  of  fused  matter  which  has  cooled  off  upon 
the  surface.  The  centre  is  supposed  to  be  still  in  a  state 
of  igneous  fusion,*  while  the  cooled  surface  forms  a  crust 
upon  which  all  the  substances  which  maintain  our  pre- 
sent existence  are  found.  To  this  crust  the  observations 
of  geologists  have  been  confined,  and  they  have  been 
able  to  lay  down  certain  definite  laws  for  the  guidance 

*  There  are  many  phenomena  which  support  this  opinion,  and 
which,  indeed,  seem  inexplicable  upon  any  other  theory.  Thus,  in 
mines  and  artesian  wells,  it  has  been  observed  that  a  depth  is  soon 
reached,  which  the  ordinary  surface  changes  of  temperature  no  longer 
affect,  and  that,  as  we  descend,  we  find  a  heat  continually  increasing. 
This  increase  is  found  to  be  one  degree  of  Fahrenheit's  thermometer  for 
every  55  J  feet,  so  that  at  less  than  1-700  of  the  earth's  radius  a  tem- 
perature of  3600°  will  be  obtained.  At  1-50  of  the  distance  from  the 
centre,  therefore,  we  may  conclude  that  every  thing  is  in  a  state  of 
fusion. 


144  MINES  AND  MINING. 

of  practical  men,  which  are  as  positive  as  any  other 
rules  deduced  from  the  study  of  nature. 

The  most  superficial  knowledge  is  sufficient  to  deter- 
mine the  fact  that  this  crust,  of  which  we  have  been 
speaking,  is  not  a  homogeneous  mass,  but  is  composed  of 
quite  a  variety  of  substances  commonly  known  as  mine- 
rals. These  are  found  in  various  positions  and  in  vari- 
ous degrees  of  aggregation,  and  to  their  masses  geolo- 
gists have  applied  the  generic  term,  rock. 

Every  one  must  have  noticed  that  some  rocks  split  up 
readily  into  layers,  while  others  only  afford  irregular 
masses  when  broken,  and  that  the  former  lie  in  regular 
strata  superimposed  upon  one  another,  while  the  latter 
present  no  indication  of  such  an  arrangement.  The  for- 
mer are  called  stratified,  the  latter  non-stratified  or  crys- 
talline rocks.  The  latter  pi-esenting  all  the  appearances 
of  having  cooled  from  a  state  of  fusion,  have  received 
the  additional  name  of  Plutonian  or  igneous  rocks,  while 
the  former,  resembling  the  deposits  now  taking  place 
from  turbid  water,  are  called  also  Neptunian  or  sedi- 
mentary rocks.  When  these  have  come  in  direct  con- 
tact with  the  igneous  rocks,  still  fluid,  the  heat  of  the 
fused  mass  has  produced  a  change  in  the  character  of  the 
sedimentary  rock,  and  without  destroying  its  stratifica- 
tion has  rendered  it  crystalline.  The  deposits  thus  al- 
tered have  received  the  name  of  metamorphic  rocks. 

If  the  earth  had  never  been  subject  to  violent  convul- 
sions, we  might  imagine  the  layers  of  these  sedimentary 
and  metamorphic  rocks  surrounding  it  in  segments  of 
concentric  spheres,  like  the  coats  of  an  onion.  But  in 
reality,  the  surface  has  been  disturbed  both  before  and 


MINES  AND  MINING.  145 

after  the  deposition  of  these  rocks.  We  have,  therefore, 
numerous  irregularities  in  the  position  of  the  layers. 
Great  masses  of  crystalline  rock,  during  those  terrible 
convulsions  which  characterized  the  early  ages  of  the 
world,  have  been  thrown  violently  up  from  the  fused 
centre,  upheaving  the  superficial  strata.  Sometimes 
this  upheaval  seems  to  have  been  in  the  form  of  a  great 
wave,  rolling  under  a  wide  area,  so  that  half  a  conti- 
nent has  been  lifted  up  without  greatly  disturbing  its 
surface.  At  others,  the  melted  matter  has  been  forced 
up  in  a  single  circumscribed  jet ;  has  burst  through  the 
crust  turning  up  its  layers,  and  protruding  above  in  high 
hills  or  mountain  masses.  The  traveler,  therefore,  as  he 
passes  over  the  broken  edges,  in  approaching  the  centre 
of  upheaval,  goes  over  them  in  the  order  of  succession 
from  above  downward,  but  after  crossing  the  ridge,  finds 
them  arranged  in  the  reverse  order.  Now  it  is  evident, 
that  if  water  should  have  swept  over  these  displaced 
strata,  with  great  violence,  it  would  have  removed  the 
surface,  and  worn  them  irregularly,  in  accordance  with 
their  relative  hardness,  forming  hills  and  valleys  of  de- 
nudation. Again,  should  a  sea  have  rolled  for  any  time 
over  the  upturned  edges  of  the  broken  rocks,  stratifica- 
tion would  again  have  taken  place,  and  as  this  would 
necessarily  form  an  angle  with  the  original  direction  of 
the  layers,  we  would  have  what  is  called  unconformable 
stratification.  These  may  again  be  worn  by  water,  and 
in  the  new  hollows,  still  later  deposits  may  occur,  so  that 
it  would  be  easy  to  make  gross  errors  in  regard  to  the 
age  of  rocks,  if  we  had  not  some  guide  to  show  us  the 
order  of  the  deposits.  We  find  an  index  of  this  in  a 
13 


146  MINES  AND  MINING. 

careful  study  of  the  succession  of  the  strata,  but  chiefly 
in  the  fossils  which  the  different  formations  contain. 

In  the  foregoing  remarks  we  have  spoken  in  accord- 
ance with  prevailing  geological  opinions,  to  which  it  is 
well  now  to  give  a  more  formal  expression.  In  the  cool- 
ing of  the  crust  of  the  earth,  we  take  it  for  granted  that 
there  must  have  been  much  contraction.  This  contrac- 
tion must  of  course  compress  the  central  fluid,  and  be- 
ing unequally  acted  on,  it  must  break  out  at  the  point  of 
least  resistance.  Other  causes  besides  this  contraction, 
may  act  to  produce  the  occasional  escape  of  the  central 
liquid.  Through  the  rents,  however  made,  fused  matter 
may  be  extruded,  and  in  this  manner,  many  have  ac- 
counted for  the  existence  of  metallic  veins,  and  for  the 
greater  certainty  of  continued  value  in  the  regular 
veins.  This,  however,  is  a  subject  to  which  we  shall 
presently  recur. 

The  first  geological  division  of  rocks  was  into  prima- 
ry or  primitive  and  secondary.  The  term  primitive  or 
primary  was  applied  indiscriminately  to  all  crystalline 
rocks,  while  secondary  was  the  title  of  all  the  stratified 
rocks.  The  facts  of  the  science,  however,  began  soon 
to  accumulate  so  rapidly,  that  they  could  no  longer  be 
crowded  into  such  narrow  limits.  The  secondary  rocks 
were,  therefore,  divided  into  transition,  secondary  and 
tertiary.  The  first  of  these  terms  was  applied  to  the 
lower  stratified  rocks,  which,  though  sedimentary,  never- 
theless, contain  abundance  of  crystalline  minerals.  The 
more  recent  deposits  were  called  tertiary,  and  everything 
between  the  two  retained  the  old  name  of  secondary. 
The  term  primary  is  now  used  very  loosely,  some  writers 


MINES  AND  MINING.  147 

confining  it  strictly  to  azoic  rocks,  or  those  without  orga- 
nic remains,  while  others  extend  it  to  the  palseozoic  series, 
or  those  in  which  we  find  the  earliest  traces  of  organiz- 
ed forms.  Indeed,  this  whole  system  of  nomenclature 
is  gradually  passing  away,  but  as  it  is  still  partially  em- 
ployed we  shall  presently  give  a  table  of  it.  It  will 
first,  however,  be  necessary  to  explain  briefly  the  terms 
applied  to  the  principal  varieties  of  rock.  Those  who 
wish  more  minute  information,  must  have  recourse  to 
works  on  mineralogy  and  geology. 

Granite  is  a  mixture  of  feldspar,  quartz  and  mica,  in 
varying  proportions.  When  studded  with  crystals  of 
feldspar,  it  is  called  porphyritic  granite.  If  hornblende 
takes  the  place  of  mica,  the  resulting  rock  is  sienite. 

Porphyry  is  a  mass  of  feldspar  containing  crystals  of 
the  same  mineral. 

G-neiss  is  only  a  stratified  granite,  resulting  from  the 
uniform  direction  of  the  mica. 

Trachytes  are  the  products  of  old  volcanos,  which 
have  sometimes  flowed  out  as  lava,  and  sometimes  have 
merely  formed  a  pasty  mass.  Like  porphyry,  they  are 
composed  of  a  feldspar  base  and  often  contain  imbedded 
crystals  of  that  mineral. 

Basalt  is  the  eruption  of  more  recent  volcanos  than 
those  which  give  rise  to  trachyte.  It  has  a  tendency  to 
separate  into  hexagonal  prisms  of  great  size,  composed 
of  segments  fitting  into  one  another  by  means  of  a 
rounded  head  adapted  to  a  saucer-like  depression.  Mine- 
ralogically,  it  consists  of  feldspar  and  augite,  and  often 
contains  distinct  crystals  of  one  or  both  of  these  min- 
erals. 

Trap  or  greenstone  is  a  dark,  heavy  rock,  containing 


148  MINES  AND  MINING. 

feldspar  and  hornblende,  and  is  either  crystalline  or  com- 
pact. 

Lavas  are  the  eruptions  of  modern  volcanos,  and  are 
usually  formed  in  their  strata  on  the  sides  of  the  moun- 
tains whence  they  have  issued. 

Schists  or  schistose  minerals  are  those  which  split  easily 
in  their  layers. 

Sand  is  a  term  usually  applied  to  loose  particles  of 
quartz.  Should  they  be  agglutinated  by  a  cement,  the 
resulting  rock  is  a  sandstone. 

Calcareous  rocks  are  composed  of  carbonate  of  lime, 
mixed  sometimes  with  carbonate  of  magnesia.  In  the 
-latter  case,  the  rock  is  called  dolomite.  Marble,  Iceland 
spar,  chalk  and  limestone  are  the  common  species  of  this 
class  of  rocks. 

The  table  we  have  selected  is  that  of  Sir  H.  T.  De  la 
Beche,  which  shows  the  order  of  succession  of  the  strata 
of  Western  Europe. 

UPPER  STRATIFIED,  OR  FOSSILIFEROUS  ROCK. 

I.  TERTIARY,  OR  CAINOZOIC. 

II.  SECONDARY,  OR  MESOZOIC. 

III.  PRIMARY,  OR  PALEOZOIC. 

I.  Tertiary,  or  Cainozoic. 

(a.  Mineral  accumulations  of  the  present  time. 
b.  Pleistocene.* 
c.  Pleiocene. 

B.  Middle  Tertiary,          Miocene. 

C.  Lower  Tertiary,  Eocene. 


*  These  terms  are  combinations  of  Greek  comparatives  and  super- 
latives, with  a  word  denoting  recent.  Thus  Pleistocene  indicates  those 
layers  which  have  the  greatest  number  of  recent  species.  Pleiocene 
those  which  have  more  than  the  strata  below  them,  Miocene,  those 
which  have  fewer,  and  Eocene  (dawn  of  recent,)  those  in  which  the 
existing  types  just  begin  to  show  themselves. 


MINES  AND  MINING. 


149 


A.  Cretaceous 
Group, 


B.  Marine  equivs 
lents  of 


C.  Jurassic  or 
Oolitic  Group, 


D.  Triassic  Group,  - 


II.  Secondary,  or  Mesozoic. 

a.  Chalk  of  Maestricht  and  Denmark. 

b.  Ordinary  chalk,  with  and  without  flints. 

c.  Meerschaum  beds,  or  upper  green  sand. 

d.  Gault. 

e.  Shanklin  sands,  vecten,  neocomian,  or  lower 

green  sand. 

a.  Wealden  clay,     ~|  Organic   remains   in  these 

b.  Hastings  sands,  j-     are  of  a  fluviatile,  lacus- 

c.  Purbeck  series,  J      trine  or  estuary  character; 
a.  Portland  oolite  or  limestone. 

c.  Portland  sands 

d.  Kimmeridge  clay. 

e.  Coral  rag  and  its  accompanying  grits. 
/.  Oxford  clay,  with  Kelloway's  rock. 

g.  Cornbrash. 

h.  Forest  marble  and  Bath  oolite. 
i.  Fuller's  earth,  clay  and  limestone. 
k.  Inferior  oolite  and  its  sands. 
I.  Lias,  upper  and  lower,  with  its  intermediate 
marlstone. 

a.  Variegated  marls,  Marnes  Irishes,  Keuper. 

b.  Muschelkalk. 

c.  Red   sandstone,  Grds   Bigarr£,  Bunter  sand- 

stein. 


III.  PKIMARY  on  PALAEOZOIC. 


(a.  Zechstein,  dolomitic,  or  magnesian  limestone. 
b.  Rothe  todte  liegende,  lower  new  red  conglo- 
merate and  sandstone,  gres  rouge. 

B.  Marine    equiva-  f  a.  Coal  measures,  terrain   Houiller,  Stein  Koh- 
lents  of  \  len  Gebirge. 

(a.  Carboniferous  and  mountain  limestone,  with 
its  coal,  sandstone,  and  shale  beds,  in 
some  districts.  Calcaire  carbonize. 
Berg  kalk. 

[_  b.  Carboniferous  slates  and  yellow  sandstone. 
D.  Devonian  group.  {  Various  modifications  of  the  Old  Red  Sandstone 

.  Upper:    Ludlow  rocks,  Wenlock  shale  and 
,,    Q  limestone,  Woolhope  limestone. 

)UP-  1    ft.  Middl«:  Caradoc  sandstone  and  conglomerate. 
Llandeilo  and  Bala  beds. 

13* 


f  a.  Upper 
I  li 

1   b.  Middle 
[  c.  Lower : 


150 


MINES  AND  MINING. 


F.  Cambrian  group. 


Barmouth  sandstones,  Penrhyn  slates,  &c. 
Various  rocks  subjacent  to  the  Silurian  se- 
ries in  Wales  and  Ireland,  and  above  the 
mica  and  chlorite  slates,  quartz,  and  other 
rocks  of  Anglesea  and  part  of  Caernarvon- 
shire. Unknown :  probably  primitive. 


MINERAL    VEINS. 

The  metallic  products  of  the  earth  are  found  in  a 
great  variety  of  situations.  These  have  been  classified 
under  the  following  heads : 

I.  SUPERFICIAL  OR  ALLUVIAL. 

a.  Constituting  the  mass  of  a  bed  or  stratified 
deposit. 

II.  STRATIFIED.        -i    b.  Disseminated  through  sedimentary  rocks. 

c.  Originally  deposited  from  aqueous  solution, 
but  since  metamorphosed. 

a.  Masses  of  eruptive  origin. 

b.  Disseminated  in  eruptive  rocks. 

c.  Stockwerke  deposits.  Irregular 

III.  UNSTRATIFIED       d.  Contact  deposits. 
MINERAL  VEINS.     ]   e.  Fahlbands. 

/.  Segregated  veins. 

g.  Gash  veins.  Regular. 

h.  True  or  fissure  veins. 

I.  Superficial  or  Alluvial  Deposits.  All  the 
alluvium  that  we  have  upon  the  surface  of  the  earth  is 
the  result  of  the  wearing  away  of  older  formations.  If 
a  mass  of  rock,  subjected  to  the  wasting  action  of  the 
water,  frost,  and  atmospheric  influences,  should  contain 
metallic  substances,  we  must  expect  to  find  them  mixed 
up  with  the  sand  and  gravel  which  are  formed  from  its 
ruins.  These  alluvial  districts  are  often  of  great  extent, 
and  though  the  working  of  them  cannot  be  properly 
called  mining,  they  furnish  large  amounts  of  the  most 
valuable  metals.  Most  of  the  gold,  much  of  the  tin, 


MINES  AND  MINING.  151 

and  all  the  platinum  of  commerce,  comes  from  such 
workings. 

The  position  of  these  different  metals  varies  considera- 
bly. The  alluvial  gold  is  usually  found  at  all  depths  of 
the  soil  in  which  it  occurs.  Tin,  on  the  contrary,  gene- 
rally lies  below  the  surface,  and  is  covered  in  by  a 
greater  or  less  depth  of  gravel,  sand,  or  clay,  and  some- 
times peat.  In  order  to  get  at  the  tin  gravel,  it  is 
necessary  first  to  remove  this  overlying  earth,  when  the 
metalliferous  pebbles  will  be  found,  generally  lying  upon 
the  primitive  rock. 

The  amount  yielded  by  these  washings  is  very  great. 
Every  one  knows  that  the  majority  of  the  gold  in  Cali- 
fornia, comes  from  the  surface  washings.  All  the  Austra- 
lian, and  nearly  all  the  Russian  gold,  so  far,  has  been 
produced  in  that  way.  When  we  know  that  California, 
in  1853,  produced  250,000  pounds  troy  of  the  precious 
metal,  Australia  210,000,  and  Russia  64,000,  we  see 
the  immense  value  of  these  superficial  deposits.  Of 
platina,  during  her  period  of  greatest  mining  activity, 
Russia  produced  nearly  five  thousand  pounds  annually. 
Of  tin,  Banca  alone  produces  from  her  alluvial  deposits, 
5,000  tons  a  year. 

Stratified  Beds.  Under  this  head  are  included  all 
metallic  deposits  which  have  evidently  been  formed  at 
the  same  time  with  the  sedimentary  rocks  in  which  they 
occur.  The  best  illustration  of  this  method  of  occur- 
rence of  metalliferous  beds  is  to  be  found  in  the  seams 
of  iron  ore  interstratified  with  the  coal  in  this  country 
and  in  Great  Britain.  When  the  more  valuable  metals 
are  found  in  such  layers,  the  deposits  are  usually 


152  MINES  AND  MINING. 

regarded  with  suspicion.'  They  rarely  increase  in  rich- 
ness as  they  descend,  and  they  cannot  be  expected  to 
"hold  out"  sufficiently  to  justify  any  large  investment 
for  their  development.  There  are  exceptions  to  this 
rule,  however,  as  we  shall  see,  when  we  come  to  speak 
of  the  Mansfield  schists. 

Unstratified  Deposits.  Under  this  head,  we  find 
the  most  valuable  collections  of  metallic  ores.  They 
are  divided  in  our  tables  under  two  heads,  regular  and 
irregular  deposits. 

IRREGULAR  DEPOSITS.  1.  Eruptive  Masses.  These  are 
aggregations  of  rock  resembling  the  surrounding  non- 
metalliferous  rocks.  The  ores  which  most  frequently 
occur  in  this  manner  are  the  oxides  of  iron,  which  seem 
to  have  been  thrown  up  at  the  same  time  with  the  igne- 
ous rocks  in  which  they  are  found.  The  great  iron- 
ridges  of  the  West  are  good  examples  of  this  form  of 
metallic  deposit.  They  either  form  ridges,  parallel  with 
those  of  the  neighboring  strata,  or  assume  the  form  of 
rounded  masses,  which  have  evidently  burst  up  from 
below,  fracturing  the  crust  upon  the  surface,  and  fusing 
or  otherwise  changing  the  strata  in  immediate  contact 
with  them. 

2.  Disseminated  in  eruptive  rocks.  It  often  happens 
that  in  a  great  upheaval  of  trap,  we  find  numerous  me- 
tallic particles,  widely  diffused  through  the  entire  mass 
of  rocks.  In  this  manner  platina  sometimes  occurs. 
Magnetic  iron  is  found  in  such  abundance  diffused 
through  the  trap  at  Tabey,  in  Sweden,  that  it  can  be 
worked  to  advantage.  At  Geyer,  in  Saxony,  small 
thread-like  veins,  and  minute  particles  of  tin,  are 
diffused  through  a  great  mass  of  granite. 


MINES  AND  MINING. 
FIG.  1.* 


153 


STOCKWERKE. 

3.  Stockwerke.  A  stockwerk  is  a  series  of  small 
veins  intersecting  one  another  and  ramifying  through  a 
mass  of  rock,  which  often  contains  also  minute  particles 
disseminated  through  it.  The  name  has  been  given  to 
them  because  they  are  worked  in  different  stages  or  sto- 
reys, one  above  another.  For  the  same  reason,  the 
English  call  them  floors.  Tin  occurs  in  this  manner, 
both  in  Cornwall  and  in  Saxony. 

FIG.  2. 


CONTACT    DEPOSIT. 
a  Deposit  of  ore  between  two  formations. 

4.  Contact  Deposits.  These  metalliferous  beds  are 
formed,  as  their  name  implies,  at  the  point  of  contact  of 
two  formations  dissimilar  in  their  geological  and  mine- 
ralogical  character.  When  a  mass  of  eruptive  rock, 
(trap,  for  example,)  breaks  through  another  formation, 

*  This  and  the  following  illustrations  are  taken  from  Whitney's 
"  Metallic  Wealth  of  the  United  States." 


154  MINES  AND  MINING. 

modifying  its  mineral  contents,  a  line  of  ore  will  often 
be  found  separating  the  two  kinds  of  rock.  If  not 
exactly  upon  the  dividing  line,  it  occurs  at  no  great 
distance  from  it,  and  preserves  a  general  parallelism 
with  it.  Or  metalliferous  minerals  may  be  found  lying 
between  two  successive  overflows  of  igneous  rock,  or 
diffused  through  both  of  them  in  the  neighborhood  of 
the  separating  surface.  Thus,  the  iron  ores  of  the 
Hartz  follow  the  contact-planes  of  the  trap  and  the 
uplifted  slates ;  and  those  of  the  Vosges  surround  a 
central  nucleus  of  porphyry,  and  line  all  the  cavities  of 
the  fracture  produced  by  the  upheaval.  The  copper 
ores  of  Monte  Catini,  in  Tuscany,  are  developed  along 
the  line  of  outcrop  of  the  gabbro,  a  rock  resulting  from 
the  metamorphic  action  of  serpentine  upon  the  cretace- 
ous strata. 

5.  Fahlbands.  These  are  best  developed  in  Norway, 
at  the  silver  mines  of  Kongsberg.*  There,  in  the  crys- 
talline states,  occur  parallel  belts  of  rock  of  very  con- 
siderable length  and  breadth,  impregnated  with  the 
sulphurets  of  iron,  copper,  and  zinc,  with  a  little  lead 
and  silver.  These  are  disseminated  through  the  rock 
in  such  minute  portions  as  to  be  hardly  visible,  and 
only  to  be  recognized  by  their  tendency  to  decompose, 
and  thus  to  give  the  rock  a  rotten  appearance.  To  this 
they  owe  the  name  "fahlband,"  or  "rotten  belt,"  the 
word  fahl  being  a  corruption  of  faul,  the  miners  term 
for  a  rotten  rock. 

These  belts  at  Kongsberg  exhibit  the  general  charac- 

*  They  have  been  traced  for  several  miles.  The  greatest  breadth 
of  any  one  of  them  is  a  thousand  feet. 


MINES  AND  MINING.  155 

ter  of  the  rest  of  the  strata  in  the  vicinity,  having  the 
same  direction  and  inclination,  and  being,  like  them, 
schistose.  The  quantity  of  metallic  matter  contained 
in  them  is  generally  small,  and  rarely  pays  for  working. 
They  are,  however,  traversed  by  true  veins,  containing 
silver  ores,  and  these  are  only  productive  where  they 
pass  through  the  fahlband.  The  chief  mining  value, 
therefore,  of  these  strata,  results  from  their  enriching 
influence  on  the  true  veins  which  intersect  them.  Even 
with  these,  the  mining  here  is  very  expensive. 

Deposits  of  the  kind  we  have  just  been  describing, 
under  these  five  heads,  while  often  developed  to  such  an 
extent  as  to  be  valuable,  are  generally  inferior  to  true 
veins.  They  are  not  so  deep,  have  gangues  which  are 
hardly  to  be  distinguished  from  the  adjoining  rocks,  and 
often  are  destitute  of  any  proper  vein-stone.  As  a  gene- 
ral rule,  they  cannot  be  worked  to  the  same  advantage 
as  the  regular  deposits,  since  the  miner  can  rarely  have 
any  security  that  they  will  hold  out  sufficiently  to  justify 
the  necessary  expenditure. 

REGULAR  DEPOSITS.  These  are  classified  under  three 
different  forms,  which  are  not  always  easily  distinguished 
from  one  another.  Surface  examination  is  often  insuffi- 
cient to  enable  the  most  experienced  observer  to  decide 
whether  a  true  vein  exists,  and  an  exploration  of  some 
depth  below  the  surface  is  absolutely  necessary  to  settle 
the  question. 

Werner  defines  veins  as  "mineral  repositories  of  a 
flat  or  tabular  shape,  which  traverse  the  strata  without 
regard  to  stratification,  having  the  appearance  of  rents 
or  fissures  formed  in  the  rocks,  and  afterwards  filled  up 


156  MINES  AND  MINING. 

•with  mineral  matter  differing  more  or  less  from  the 
rocks  themselves."  Whitney  objects  to  this  definition 
as  excluding  many  veins  which  do  not  traverse,  but  run 
parallel  with  the  strata,  and  others  which  occur  in 
unstratified  rocks.  His  definition  is,  *'  an  aggregation 
of  mineral  matter  of  indefinite  length  and  breadth,  and 
comparatively  small  thickness,  differing  in  character 
from,  and  posterior  in  formation  to,  the  rocks  which 
enclose  it."  Both  these  definitions  include  veins  which 
do  not  contain  metal. 

Weissenbach  divides  true  veins  into  six  different  classes. 

1.  Veins  of  sedimentary  origin.     If  a  fissure  should 
exist  in  a  rock  upon  which  a  new  deposit  of  a  sediment- 
ary character  was  taking  place,  it  must,  of  course,  be 
filled  by  the  sedimentary  matter,  which  will  be  stratified 
in  it  just  as  it  is  on  the  general  surface  of  the  rock. 

2.  Veins  of  attrition.     These  are  fissures  filled  with 
matter  introduced  by  purely  mechanical  means,  such  as 
the  falling  of  fragments  of  wall  rock  from  above,  or  friction 
of  their  sides  upon  one  another.     Many  ore-bearing  veins 
exhibit  phenomena  of  this  kind. 

3.  Veins  of  infiltration,  or  stalactitic  veins.     These 
result  from  the  filling  of  fissures  by  incrustation  of  the 
sides  with  calcareous  matter  deposited  from  water,  pre- 
cisely in  the  same  manner  in  which  stalactites  are  formed 
in  caverns. 

4.  Plutonic  veins.     These    are   fissures   filled   with 
mineral  matter  injected  from   beneath,  or  pressed  up- 
wards while  in  a  plastic  state. 

5.  Segregated  veins. 

6.  Metalliferous  veins,  proper. 


MIXES  AND  MINING. 


157 


Before  going  further  in  the  description  of  true  veins, 
•we  pause  to  explain  certain  technical  terms  in  common 
use  among  miners.  Veins,  as  we  have  already  said, 
may  be  barren  of  metal ;  hence,  the  word  vein  is  a 
generic  term.  Those  which  contain  ores  are  called 
lodes,  and  those  which  are  not  productive,  and  are  not 
in  the  usual  direction  of  the  lodes  of  a  district,  are 
termed  cross  courses.  The  rock  in  which  the  lode  is 
found  is  called  the  country.  The  dip  or  inclination  of  the 
vein  towards  the  horizon,  is  its  hade,  slope,  or  underlie, 
and  its  superficial  length  is  its  run,  bearing,  or  direc- 
tion. Strings  are  small  filaments  into  which  the  vein 
splits,  and  these,  when  very  small,  are  called  threads. 
The  two  sides  of  the  cavity,  which  contain  the  lode,  are 
called  iv alls  ;  and  if  the  vein  has  a  considerable  inclina- 
tion, its  upper  boundary  is  called  the  hanging  wall,  and 
its  lower,  the  foot  wall. 

We  now  resume  the  consideration  of  the  classes  of 
regular  deposits. 


Fio. 


SEGREGATED   VEINS. 

a  Segregated  mass  of  ore  cropping  out  at  the  surface.    6  Parallel  layer  not  extend- 
ing upward  so  far. 

14 


158 


MINES  AND  MINING. 


1.  Segregated  veins.  These  are  veins  which  have  a 
crystalline  structure,  or  a  gangue  differing  from  the 
adjacent  rocks,  but  which  do  not  appear  to  occupy  a 
previously  existing  fissure.  They  seem  to  have  been 
gradually  separated  by  chemical  action  from  the  sur- 
rounding formation ;  hence  their  name,  segregated 
veins.  They  differ  from  true  veins  in  their  relation  to 
the  adjacent  stratification.  They  lie  parallel  with  the 
cleavage  of  the  surrounding  rocks.  The  downward 
extent  varies  greatly,  and  the  mass  generally  thins  out, 
and  entirely  disappears  at  a  greater  or  less  distance 
from  the  surface.  In  the  Rammelsberg,  one  of  the 

FIG.  4. 


SECTION  OF  THE  RAMMELSBERG. 

a  c  Principal  mass   of  ore  lying  in  the  direction  of  the  argillaceous  shales.    6 
Branch  four  hundred  feet  deep,  dipping  further  from  the  perpendicular. 

Hartz  mountains,  a  famous  mine  of  this  character  oc- 
curs. The  main  mass  of  ore  lies  in  the  direction  of  the 
argillaceous  slates  of  which  the  mountain  is  composed. 
At  the  depth  of  about  four  hundred  feet,  it  sends  off  a 
branch  which  crosses  the  dip  of  the  slates  at  an  acute 


MINES  AND  MINING.  159 

angle.  The  greatest  thickness  of  the  mass  is  more  than 
one  hundred  and  fifty  feet,  and  its  length  about  nine- 
teen hundred.  As  it  descends,  however,  it  grows 
smaller.  Thus,  at  eight  hundred  and  fifty  feet,  it  has 
contracted  to  twenty  feet  in  thickness  and  seven  hun- 
dred and  fifty  in  length.  It  has  no  proper  vein-stone, 
but  is  a  mass  of  sulphurets  of  iron,  zinc,  lead,  and 
copper,  and  almost  entirely  destitute  of  gangue.  The 
veins  of  gold  quartz  are  usually  of  this  character,  oc- 
curring in  belts  which  dip  with  the  stratification. 

These  deposits  cannot  be  relied  upon  as  true  veins. 
They  are  almost  always  richest  at  the  surface,  and  are 
liable  to  thin  out,  or  ^en  entirely  to  disappear.  The 
ore  is  distributed  through  them  with  no  regularity, 
occurring  usually  in  nests  and  pockets,  arranged  in  a 
general  linear  direction,  and  connected  by  mere  threads 
of  ore  or  barren  vein-stone. 

FIG.  5. 


MS 


GASH  VEINS. 

a  Upper  series  of  veins,     b  Stratum  cutting  off  the  upper  series  entirely  from  c, 
the  lower  series  of  veins,  which  are  independent  fissures. 

2.  Crash  veins.  These  veins  occupy  pre-existing 
fissures,  which  are  not  attended  by  any  considerable 
breaking  up  of  the  strata.  When  there  is  a  marked 


160  MINES  AND  MINING. 

difference  in  the  character  of  the  rocks  which  make  up 
any  particular  series,  the  fissures  are  usually  confined 
to  one  member  of  the  series,  and  disappear  on  passing 
to  the  next.  If  the  same  rock  occurs  again  on  the  other 
side  of  the  interpolated  mass,  the  veins  may  be  found  in 
it.  Lateral  branches  are  often  found  in  connection 
•with  the  main  fissures,  and  usually  at  right  angles  to 
them. 

The  origin  of  this  class  of  fissures  has  been  attributed 
to  the  shrinkage  of  the  rocks,  either  during  cooling,  or  in 
consequence  of  a  subsequent  exposure  to  long-continued 
heat.  Thus,  mineral  contents  may  have  been  deposited 
as  sediment,  or  segregated  from -the  mass  of  the  rock. 
They  differ  from  true  veins,  in  not  showing  such  distinct 
selvages,  and  in  the  less  decidedly  crystalline  character 
of  their  vein-stones.  They  are  generally  found  in  those 
sedimentary  rocks  which  have  undergone  but  little 
change,  and  still  retain  the  original  lines  of  stratifica- 
tion. They  are  still  less  reliable  than  segregated  veins, 
but  their  number  often  makes  up  for  their  limited  ex- 
tent, so  that,  while  any  individual  vein  cannot  be 
expected  to  hold  out,  the  region  in  which  they  occur, 
may,  for  a  time,  furnish  a  large  amount  of  ore. 

3.  True  veins.  These  are  fissures  in  the  crust  of  the 
earth,  of  indefinite  length  and  depth,  which  have  been 
subsequently  filled  with  mineral  matter.  As  they  are 
believed  to  have  originated  in  a  fracture  of  the  strata 
caused  by  the  action  of  a  powerful  force  far  below,  they 
may  be  expected  to  extend  indefinitely  downward.  Ex- 
perience so  far  verifies  this  opinion  that  no  well  devel- 
oped and  well  defined  vein  has  yet  been  found  termina- 


MINES  AND  MINING.  161 

ting  entirely  at  any  depth  which  has  been  reached,  while 
nothing  is  more  common  than  a  total  disappearance  of 
the  other  forms  of  deposits  which  we  have  described. 

The  length  of  veins  upon  the  surface  varies  greatly. 
Some  have  been  traced  for  miles,  and  differ,  as  to  their 
metallic  contents,  in  different  parts  of  their  course,  some 
points  being  entirely  barren,  while  others  are  well  charged 
with  ore.  As  a  general  rule,  the  longer  the  vein,  the 
more  liable  is  it  to  prove  productive  somewhere.  Some 
of  the  great  veins  in  Mexico  have  been  followed  more  than 
six  miles,  and  opened  and  worked  in  many  places.  The 
length  and  breadth  of  a  vein  have  no  necessary  relation. 
The  width  is  of  course  irregular,  because  when  the  frac- 
ture took  place  the  rocks  were  not  only  torn  apart,  but 
also  uplifted,  so  that  one  side  of  the  crack  has  slid  upon 
the  other,  making  a  fissure  altogether  devoid  of  paral- 
lelism between  its  two  faces.  If  this  notion  of  the  pre- 
vious fracturing  of  the  surface  be  correct,  we  should 
expect  to  find  a  concentration  of  veins  in  certain 
regions  of  the  earth,  for  a  great  upheaval  which  should 
fracture  the  crust  in  one  place,  would  be  likely  to  cause 
numerous  cracks  all  about  the  centre  of  the  greatest 
force.  It  certainly  increases  the  probability  of  the  cor- 
rectness of  the  theory,  to  discover,  as  we  do,  the  very 
limited  and  scattered  districts  which  have  so  far  pro- 
duced the  metals  in  general  use  among  men. 

The  vein  is  not  a  mass  of  ore  exclusively.  The 
greater  portion  of  it  is  occupied  by  some  rock,  different 
from  the  surrounding  strata,  which  is  known  as  the  vein- 
stone or  gangue.  Quartz  is  the  most  common  mineral 
found  in  this  position.  It  occurs  in  a  variety  of  forms, 
14* 


162 


MINES  AND  MINING. 


usually  highly  crystalline,  especially  in  the  "  vugs,"  or 
cavities,  of  the  vein.  Each  mineral  district  appears  to 
have  vein-stones  peculiar  to  itself. 


b   d       e       f 

PART  OF  A  LODE  AT  WHEEL  JULIA,  NEAR  BIXNER  DOWNS,  CORNWALL. 

a  Bisulphnret  of  copper  and  sulphuret  of  zinc.  6  Comb  of  quartz,  c  Wall  of  in- 
durated argillaceous  matter,  d  Comb  of  quartz,  e  Large  comb  of  quartz,  with 
blende  and  copper  ores/  on  both  sides,  g  Cavity  or  vug,  in  another  comb  of  quartz. 
h  More  solid  comb  of  quartz. 

The  minerals  in  a  well  defined  lode  often  form  a 
series  of  plates,  parallel  to  the  walls  of  the  lode,  and 
containing  crystals  set  at  right  angles  to  them.  These 
crystalline  layers  are  called  combs,  and  their  faces  meet 
and  interlock  with  one  another.  Sometimes  these  are 
arranged  in  perfect  symmetry,  the  same  substances 
crystallizing  with  great  regularity  at  corresponding  dis- 
tances on  each  side  of  the  central  mass. 

In  addition  to  the  true  vein-stones,  the  lode  often 
contains  fragments  of  the  adjacent  strata,  which  appear 
to  have  been  introduced  mechanically.  These  may  be 
in  numerous  minute  pieces,  so  as  to  give  the  gangue  a 
brecciated  character,  or  they  may  be  in  large  masses. 
When  one  of  the  latter  occurs,  it  is  called  a  "  horse," 
and  the  vein  is  said  to  "take  ahorse."  The  fissure 


MINES  AND  MINING. 


163 


has  often  numerous  offshoots,  or  supplementary  fissures, 
branching  from  it;  these  are  called  "droppers,"  when 
they  leave  the  vein,  and  when  they  concentrate,  or  fall 
into  it  again,  they  are  named  "feeders."  Their  direc- 
tion and  appearance  are  important  guides  to  the  miner. 
The  vein-fissure  is  sometimes  abruptly  contracted,  and 
then  it  is  said  to  be  "nipped." 

FIG.  Y. 


TRAVERSE    SECTION    OF    A   VEIN. 


The  mass  of  vein-stone  is  usually  separated  from  the 
wall  by  thin  bands  of  clay,  or  similar  soft  substance, 
which  are  called  "selvages."  By  preventing  too  close 
adhesion  to  the  rock,  they  facilitate  the  removal  of  the 


164  MINES  AND  MINING. 

contents  of  the  vein.  The  walls  are  often  smooth  and 
grooved  as  though  the  lode  had  rubhed  against  them. 
These  surfaces  are  called  "slickensides." 

Few  veins  are  so  uniformly  rich  in  ore  as  to  pay  for 
the  entire  removal  of  their  contents.  It  is  customary, 
therefore,  to  confine  the  operations  to  the  rich  por- 
tions of  the  vein,  leaving  the  poor  undisturbed.  The 
waste,  unproductive  matter  brought  to  the  surface,  is 
called  deads  or  attle.  The  rich  bunches  are  very  irregu- 
lar in  their  occurrence,  and  the  chances  of  finding  them 
in  any  particular  spot  can  only  be  estimated  after  a 
thorough  examination  of  the  system  of  lodes  in  the  dis- 
trict under  consideration.  One  kind  of  rock  usually  is 
richer  than  any  other,  and  this  presents,  of  course,  the 
greatest  inducements  for  a  liberal  expenditure  of  time 
and  money.  Where  there  are  numerous  parallel  veins, 
the  run  of  the  courses  of  ore,  or  the  relation  of  the  rich 
masses  to  the  entire  vein,  will  usually  be  found  to  be 
similar  in  all  the  lodes.  When,  therefore,  one  has  been 
properly  opened  and  explored,  it  serves  as  a  guide  to 
all  the  rest.  It  requires,  however,  no  little  experience 
to  decide  upon  the  characters  which  justify  working, 
and  even  then,  the  longest  acquaintance  with  these  sub- 
jects will  often  serve  to  mislead  the  miner  who  attempts 
to  apply  the  rules  of  one  district  to  another  mining 
region. 

The  irregularities  of  the  fissures,  of  course,  involve 
the  practical  miner  in  numerous  difficulties.  A  vein  has 
been  known  to  dip  parallel  with  the  strata,  and  then  to 
be  shifted  to  a  plane  twenty  or  thirty  feet  distance, 
without  any  dislocation  of  the  surrounding  rock.  In 


MINES  AND  MINING.  165 

such  a  case,  a  fissure  may  connect  the  two  fragments  of 
the  vein,  and  yet  be  so  small  as  to  escape  attention. 
At  Holzappel,  in  Baden,  there  is  such  a  shifted  vein, 
in  which  the  fissure,  though  cut  by  a  level,  was  entirely 
overlooked,  and  the  lode  was  not  discovered  till  after  a 
shaft  had  been  sunk  from  the  level,  in  the  other  portion 
of  the  vein.  A  true  vein  also  may  for  some  distance 
coincide  with  the  dip  of  the  strata,  and  may  send  out 
offshoots  which  follow  the  planes  of  cleavage,  and  yet 
the  main  fissure  in  the  rest  of  its  course  may  cut  the 
different  layers  across.  In  such  a  case,  it  will  be  neces- 
sary to  cut  the  lode  for  some  distance,  in  order  to  ascer- 
tain whether  it  be  a  genuine  fissure-vein,  and  whether 
the  branches  parallel  to  the  stratification,  have  not  been 
opened  along  the  line  of  easiest  fracture. 

After  the  first  set  of  fissures  had  been  made  and  filled 
up,  there  was  no  reason  why  a  new  set  should  not  occur, 
since  the  crust  of  the  earth  was  still  subject  to  the  same 
influence.  There  is  abundant  evidence  of  such  subse- 
quent fractures,  in  the  numerous  secondary  veins  which 
cross  the  older  lodes,  and  "  heave"  them  to  one  side  or 
the  other.  There  are  even  examples  of  a  tertiary  set 
of  fissures  crossing  both  the  former.  We  have  already 
said  that  these  veins,  when  destitute  of  ore,  are  called 
"cross-courses;"  when  they  contain  ore,  they  receive 
the  name  of  "  contra-lodes."*  Cornwall  contains  seve- 
ral systems  of  fissures,  and  it  is  remarkable  that  those 
of  the  same  age  are  usually  parallel,  and  contain  the 

*  These  crossings  of  different  sets  of  veins  are  usually  considered 
favorable  indications  of  rich  veins,  especially  at  the  point  of  con- 
tact. 


166 


MINES  AND  MINING. 


same  varieties  of  ores  and  veinstones.  In  the  Hartz 
there  are  two  principal  directions  of  fracture.  In  the 
Freiberg  districts,  these  intersections  are  more  numer- 


a  b      c    d  e  f  g    h  i       k  k      i 

FRAGMENTS  OF  THE  DREI  PRINZEN  SPAT  VEIN.  NEAR  FREIBERG. 


a  Blende,     b  Quartz,     c  Fluor  Spar,     d  Blende,     e  Heavy  Spar.    /  Sulphnret  of 
Iron,    g  Heavy  Spar,    h  Heavy  Spar,    i  Sulphuret  of  Iron,     k  Calcareous  Spar. 

ous  than  anywhere  else,  more  than  nine  hundred  differ- 
ent veins  having  been  recognized  in  the  space  of  forty 
or  fifty  square  miles. 

In  this  country  no  such  complicated  system  has  yet 
been  discovered.  In  the  Lake  Superior  region,  the 
veins  of  any  limited  district  are  usually  parallel.  Some 
movement  of  the  planes  of  stratification  upon  one  an- 
other has  taken  place,  which  has  shifted  the  veins  for  a 
few  feet  in  the  direction  of  the  slide. 

One  of  the  most  commonly  received  opinions  as  to 
the  method  in  which  metallic  veins  have  been  formed,  is 
that  which  attributes  them  to  the  injection  of  molten 
matter  from  below  into  the  previously  formed  fissures. 


MINES  AND  MINING.  167 

This  may  be  true  of  a  limited  number  of  veins,  those 
for  instance,  which  have  igneous  veinstones,  but  it  can- 
not be  used  to  explain  the  production  of  the  majority  of 
metalliferous  lodes.  The  difference  in  the  value  of  the 
vein  in  different  members  of  the  geological  series  in 
Avhich  it  occurs,  appears  to  be  a  formidable  objection  to 
this  theory.  In  the  same  light,  also,  must  we  regard 
the  usually  unbroken  condition  of  the  walls  of  the  cav- 
ities which  contain  the  lodes. 

Another  theory  accounts  for  the  formation  of  veins 
by  sublimation  from  below  and  condensation  in  the  fis- 
sures. There  are  facts  which  accord  very  well  with  this 
opinion.  Thus,  at  Nagyag,  in  Transylvania,  metallic 
arsenic  is  deposited  upon  those  faces  of  crystals  of 
manganese-spar  which  have  been  turned  downwards. 
There  are,  however,  a  great  number  of  phenomena  which 
refuse  to  adapt  themselves  to  any  such  notion.  The 
variation  in  the  character  of  lodes  in  different  rocks  is 
as  little  explicable  upon  this  hypothesis  as  upon  that 
last  noticed.  The  presence  of  non-volatile  matter  in 
veins  has  also  been  objected,  but  it  is  not  easy  to  de- 
cide what  is,  and  what  is  not  volatile,  at  the  high  tem- 
perature of  the  earth's  centre.  The  veins  to  which  this 
theory  is  most  applicable,  are  those  of  mercury. 

At  present,  the  views  of  the  advocates  of  lateral  secre- 
tion are  most  generally  received.  Those  who  hold  these 
opinions,  believe  that  the  mineral  and  metalliferous  par- 
ticles have  been  separated  from  the  surrounding  rocks 
in  a  state  of  solution,  and  have  been  deposited  within 
the  vein  by  the  action  of  electro-chemical  forces.  It  is 
certainly  in  favor  of  this  theory,  that  the  majority  of 


168  MINES  AND  MINING. 

the  veinstones,  such  as  calcareous  spar,  quartz,  &c.,  are 
now  generally  believed  to  have  been  deposited  from 
aqueous  solution,  and  certainly  cannot  have  been  sub- 
limed by  igneous  action.  The  ores  may  also  be  depos- 
ited in  the  same  way.  Galena  has  been  made  artificial- 
ly, in  the  laboratory  of  the  chemist,  from  aqueous  solu- 
tion by  double  decomposition.  Sulphuret  of  iron  is  a 
common  product  of  the  contact  of  ferruginous  waters 
with  decaying  organic  matter.  Murchison  has  shown 
that  the  copper  ores  of  the  Permian  strata,  in  Russia, 
must  have  been  formed  in  the  same  way,  since  they  are 
accumulated  round  the  remains  of  the  stems  and  branches 
of  plants. 

The  fissures  opened  deep  in  the  crust  of  the  earth, 
may  be  supposed  to  have  been  filled  with  water  holding 
mineral  matter  in  solution.  Passing  through  the  differ- 
ent strata,  these  solutions  would  be  differently  acted 
upon  in  accordance  with  the  varying  chemical  constitu- 
tion of  the  rocks.  If  the  water  were  acidulated,  it 
would  act  upon  the  metallic  particles  with  which  it  came 
in  contact.  It  is  easy  to  see  how,  on  this  hypothesis,  a 
vein  might  be  richer  in  certain  rocks  than  in  others. 
Either  the  rock  might  contain  more  metallic  substances, 
or  it  might  act  more  readily  upon  those  in  solution  in 
vein-fissures.  That  some  action  has  taken  place  in  the 
surrounding  strata,  is  evident  from  their  alteration  in 
the  neighborhood  of  the  lode.  They  are  either  decom- 
posed and  rotten,  or  they  are  more  impregnated  with 
silicious  matter.  In  the  latter  case,  the  flinty  masses 
are  called  by  the  Cornish  miners  the  capels  of  the  lode. 

The  existence  of  electric  currents  in  veins  has  been 


MINES  AND  MINING.  169 

established  by  the  testimony  of  several  independent  ob- 
servers. They  are  supposed  to  originate  in  the  lode  and 
to  have  no  connection  with  the  great  magnetic  circles  of 
the  earth. 

Nearly  all  veins  are  characterized  near  their  surface 
by  evidences  of  atmospheric  or  other  chemical  action. 
The  surface  ores  vary  from  those  which  we  find  below, 
in  being  far  more  highly  oxydized.  Thus,  if  the  mass 
of  the  vein  contain  sulphurets,  we  find  the  surface  ores 
almost  exclusively  carbonates,  silicates  and  other  oxy- 
salts.  In  many  copper  veins,  the  copper  has  almost 
wholly  disappeared,  the  sulphurets  having  been  oxydated 
to  sulphates,  which,  being  soluble  in  water,  have  washed 
out,  leaving  a  porous  iron  ore,  or  a  peculiar  rotten, 
weathered,  stained  quartz  upon  the  surface.  This  is 
called  by  the  Germans  the  "iron  hat,"  and  by  the 
Cornish  miners  "gossan."  The  depth  to  which  these 
alterations  extend  is  very  variable.  Sometimes  it  is 
confined  to  the  surface,  the  sulphurets  remaining  unde- 
composed  up  to  the  soil.  Usually  it  reaches  to  a  depth 
of  a  hundred  feet,  and  it  has  been  known  to  be  still 
quite  evident  at  three  hundred  feet  below  the  surface. 

To  recapitulate  the  practical  points,  we  may  say  that 
true  fissure-veins  are  deep  and  do  not  run  out  or  sensi- 
bly diminish  in  contents  of  ore  at  any  depth  which  has 
yet  been  reached ;  while  segregated  and  gash  veins,  and 
the  various  irregular  deposits,  though  often  very  rich  as 
far  as  they  go,  cannot  be  relied  on  as  having  the  same 
permanence  with  a  true  vein. 


15 


170  MINES  AND  MINING. 

MINING   OPERATIONS. 

The  presence  of  valuable  veins  of  ore  is  recognized 
by  surface  indications,  or  by  a  series  of  systematic  ex- 
plorations. The  former  can  rarely  do  more  than  estab- 
lish a  vague  probability,  and  those  which  are  still  relied 
upon  in  some  places,  are  altogether  futile.  Such  are 
the  heat  of  thermal  springs,  gratuitously  attributed  to 
the  decomposition  of  pyrites ;  the  impregnation  of  run- 
ning water  with  metallic  salts  which  may  have  come 
from  some  very  remote  point.  If,  however,  a  small  rill, 
in  a  rocky  region,  should  be  discovered  to  contain  at  its 
source,  metallic  salts,  it  will  generally  be  safe  to  infer 
the  presence  of  ores  somewhere  in  its  immediate  neigh- 
borhood. Streams  impregnated  with  sulphates  of  cop- 
per and  iron,  have  been  known  to  issue  from  rocks  con- 
taining copper  pyrites,  one  of  the  most  valuable  ores  of 
that  metal.  It  must  be  borne  in  mind,  however,  that 
this  ore  may  be  diffused  through  the  strata,  and  not  con- 
centrated in  a  vein,  in  which  case,  it  will  rarely  pay  for 
the  labor  necessary  to  be  expended  upon  it.  Springs, 
heavily  charged  with  ferruginous  matters,  are  no  bad 
indications  of  the  neighborhood  of  workable  beds  of 
iron  ore,  especially  in  alluvial  and  carboniferous  re- 
gions. 

A  knowledge  of  geology  is  essential  to  any  one  who 
would  form  an  opinion  as  to  the  value  of  a  country  for 
mining  purposes.  It  enables  him  at  once  to  exclude  a 
large  number  of  minerals,  which  could  not  be  found 
in  the  regions  under  consideration.  It  saves  him  the 
trouble  of  digging  for  substances  which  there  is  no  pro- 
bability of  finding,  and  enables  him  to  seek  for  infor- 


MINES  AND  MINING.  171 

mation  where"  nature  has  been  at  the  trouble  of  disclos- 
ing it  to  him. 

A  vein  cannot  be  expected  to  escape  the  ordinary 
weathering  and  decomposing  influences  of  the  atmo- 
sphere, the  rain,  and  the  frost.  The  surface  overlying 
it  will  probably  be  covered  with  the  fragments  which 
have  been  detached  from  it.  Thus,  in  a  chrome-iron  re- 
gion, the  position  of  the  vein  is  indicated  by  the  pre- 
sence of  angular  fragments  of  the  gangue,  stained  of  a 
peculiar  yellowish  green.  In  the  Hartz  mountains,  the 
iron  hat  to  which  we  have  already  alluded,  has  been 
found  to  overlie  valuable  veins  of  lead  and  silver.  The 
weathered  and  decomposed  quartz,  and  the  porous  iron 
ore,  called  gossan,  is  in  many  regions  regarded  as  a  val- 
uable surface  indication  of  copper.  These  indications 
will  be  rendered  more  certain  by  a  careful  study  of  the 
general  character  of  the  veins  in  a  district.  Thus,  for 
example,  if  in  any  region,  ores  of  copper  should  be 
found  largely  intermingled  with  magnetic  iron,  a  defin- 
ed band  of  fragments  of  the  latter  ore  lying  upon  the 
surface,  would  afford  sufficient  inducement  for  explora- 
tion below.  When  the  ores  of  a  vein  lie  high,  they 
will  also  be  found  distributed  over  the  surface.  Thus 
the  presence  of  stains  of  carbonate  or  silicate  of  cop- 
per, in  fragments  of  rock  differing  from  the  general 
masses  of  the  country,  and  still  more  the  occurrence  of 
bits  of  sulphuret  similarly  imbedded,  would  afford  good 
reason  for  believing  a  workable  vein  of  copper  ore  to  be 
in  the  neighborhood. 

In  all  examinations  of  this  kind,  the  action  of  water 
must  be  borne  in  mind.  As  streams  sweep  from  hills 


172  MINES  AND  MINING. 

into  valleys,  they  carry  with  them  fragments  of  various 
kinds  of  rock.  By  carefully  observing  these,  and  trac- 
ing them  to  their  sources,  the  veins  from  which  the  me- 
talliferous pebbles  were  originally  detached  may  be 
found.  Water  also  acts  directly  in  exposing  to  our  view 
the  mineral  wealth  of  a  region,  by  making,  in  the  differ- 
ent ravines  and  gulleys,  so  many  natural  geological  sec- 
tions in  which  we  can  trace  the  veins.  These,  even 
though  barren,  provided  they  contain  the  same  gangue  as 
the  productive  lodes  of  the  district,  deserve  attention, 
as  they  may  become  metalliferous  in  the  course  of  their 
descent  into  the  earth. 

It  may  happen,  when  the  veinstone  is  much  harder 
than  the  surrounding  rock,  that  the  joint  action  of  air 
and  water  may  wear  away  the  latter  more  rapidly  than 
the  former,  so  that  the  v«in  may  remain  a  kind  of  wall, 
protruding  above  the  common  level  of  the  soil.  Such  a 
dyke  exists  at  Mouzias,  in  Algeria,  where  several  lodes 
of  heavy  spar  and  spathose  iron,  containing  a  little  gray 
copper,  traverse  a  soft  and  marly  soil  that  offers  little 
resistance  to  the  action  of  water.  In  consequence,  the 
heavy  rains  have  washed  away  the  softer  clay,  and  left 
the  more  solid  outcrop  of  the  lodes  standing.  In  some 
places  this  wall  is  fifteen  or  twenty  feet  high,  and  cuts 
all  the  different  formations  of  the  country. 

The  most  careful  examination  of  the  surface,  however, 
often  fails  to  communicate  any  satisfactory  information 
as  to  the  metallic  wealth  of  the  region  examined.  Then 
artificial  excavations  become  necessary.  If  the  vein  be 
well  developed  near  the  surface,  an  open  cut  or  trench 
will  often  disclose  its  character.  The  more  common  me- 


MINES  AND  MINING.  173 

thod  of  procedure,  however,  among  the  Cornish  miners 
is  what  they  term  shading  or  costeaning. '  This  consists 
in  sinking  a  series  of  pits  about  three  feet  wide,  six 
long,  and  deep  enough  to  penetrate  the  alluvial  soil  and 
sink  a  few  feet  in  the  rock.  If  the  direction  of  the  veins 
of  the  neighborhood  is  known,  this  line  of  pits  should 
cross  it  at  right  angles.  If  the  region  is  wholly  unex- 
plored, two  series  of  pits  must  be  sunk  at  right  angles 
to  one  another.  These  isolated  shafts  are  now  joined  by 
galleries,  so  that  it  is  impossible  that  any  vein  should 
escape  detection. 

The  presence  of  a  promising  vein  being  determined, 
the  next  thing  is  to  make  the  necessary  openings  for 
working.  Open  cuts  are  out  of  the  question,  for  the 
riches  of  a  vein  always  lie  deep  below  the  surface,  and 
the  upper  portions  are  usually  quite  poor.  There  are  a 
number  of  points  to  be  taken  into  consideration  in 
excavations  for  mining  purposes.  The  surface  water 
and  rain  must  be  kept  out  of  them,  and  the  greatest 
care  must  be  taken  to  get  rid  of  the  deeper  water  in  the 
simplest  and  cheapest  manner.  It  is  necessary  also  to 
provide  for  the  ventilation  of  the  mine. 

The  first  step,  if  the  conformation  of  the  country  ad- 
mits of  it,  is  to  devise  an  adit-level  or  horizontal  gallery 
from  the  lowest  possible  point  of  an  adjacent  valley  di- 
rectly upon  the  vein.  This  will,  of  course,  drain  all  the 
work  above  the  level  at  which  it  intersects  the  vein,  and 
the  skill  of  the  operator  is  shown  in  reaching  this  at  the 
least  expenditure  of  time  and  labor,  and  cutting  it  at 
the  lowest  possible  point.  Sometimes  but  a  few  feet,  at 
others  many  fathoms  of  perpendicular  descent  can  be 
15* 


174  MINES  AND  MINING. 

drained  by  these  galleries.  The  economy  is  great,  as 
they  save  the  constant  outlay  in  machinery  for  pumping 
up  the  water.  Of  such  importance  are  these  galleries 
esteemed,  that  sometimes  a  number  of  mines  are  drained 
by  a  single  adit  driven  at  their  joint  expense.  So  long 
as  the  excavations  are  kept  above  the  adit-level,  it  is  of 
course  unnecessary  to  use  machinery  for  pumping,  and 
•when  they  have  been  sunk  below  it,  the  water  need  only 
be  raised  to  it,  and  not  to  the  surface  of  the  ground. 
In  large  mines,  every  foot  saved  in  this  way  is  import- 
ant, and  large  expenditures  are  justifiable,  which  will 
effect  a  slight  reduction. 

It  is  desirable,  if  possible,  that  the  adit  should  be 
driven  on  the  vein  itself  or  close  beside  it,  so  that  it  may 
be  broken  into  from  time  to  time,  and  its  character  and 
richness  determined.  Where  this  is  impossible,  it  must 
be  driven  to  the  vein.  It  is  necessary  that  the  adit 
should  be  inclined  only  sufficiently  to  allow  for  the  ready 
flow  of  the  water.  If  it  be  too  near  a  dead  level,  it  will 
fail  to  accomplish  its  purpose,  if  too  steep,  it  will  strike 
the  vein  unnecessarily  high. 

The  next  thing  to  be  done  is  to  sink  a  shaft,  to  inter- 
sect both  the  vein  and  adit  or  a  cross-cut  leading  from 
the  latter.  If  the  vein  be  nearly  vertical,  it  is  custom- 
ary to  sink  the  shaft  directly  upon  it,  unless  its  underlay, 
or  the  angle  it  makes  with  the  perpendicular,  is  too 
irregular,  in  which  case  it  is  sunk  by  the  side  of  the 
vein  and  connected  with  it  by  cross-cuts.  When  the 
lode  has  an  underlay  of  45°,  it  is  usual  to  sink  vertical 
shafts  upon  it.  The  dip  of  the  vein  having  been  ascer- 
tained, it  is  easy  to  decide  upon  a  point  at  which  a 


MINES  AND  MINING.  175 

shaft  must  be  opened,  in  order  to  strike  it  at  a  given 
depth.  After  striking  the  vein,  the  shaft  may  be  push- 
ed through  it,  for  some  distance  into  the  non-metallifer- 
ous rock.  The  vein  can  then  be  attacked,  if  necessary, 
both  on  its  upper  and  its  under  side,  by  driving  cross- 
cuts from  the  shaft.  In  the  Lake  Superior  region,  the 
shafts  in  veins  of  such  an  underlay  are  driven  in  the 
vein  itself,  following  its  dip,  and  the  method  has  proved 
to  be  economical.  In  such  shafts,  a  double  tram-road  is 
laid,  and  the  ore  is  loaded  on  cars  in  the  levels  and  run 
up  to  the  surface.  The  verticle  shafts  are  employed  in 
England,  and  are  always  to  be  preferred  when  there  are 
several  parallel  veins  to  be  worked  by  the  same  excava- 
tions, or  when  they  are  used  in  part  for  the  purpose  of 
exploration.  The  size  of  the  opening  of  a  shaft  neces- 
sarily varies  with  the  purposes  it  is  required  to  subserve. 
If  it  is  to  be  used  as  an  engine-shaft,  or  that  in  which 
the  pumping  machinery  is  placed,  at  the  same  time  that 
ore  is  raised  through  it,  it  must  be  from  twelve  to  fifteen 
long  by  six  or  eight  wide. 

Of  course,  the  bottom  of  the  shaft  would  soon  become 
obstructed  by  the  fragments  of  the  workings,  as  well  as 
flooded  by  water,  if  measures  were  not  taken  to  remove 
both  these  accumulations.  Buckets  are  provided  for  the 
ore,  which  are  termed  by  the  Cornish  miners  kibbles. 
In  Cornwall,  they  are  made  of  sheet-iron,  and  each  holds 
about  three  hundred  weight  of  ore.  One  hundred  and 
twenty  kibbles  are  supposed  to  clear  a  cubic  fathom  of 
rock.  Until  the  shaft  has  got  below  the  depth  of  a  hun- 
dred feet,  the  only  lifting  arrangement  necessary  is  a 
windlass,  worked  by  hand.  The  kibbles  and  their  ropes 


176  MINES  AND  MINING. 

are  so  arranged  that  they  pass  one  another  in  the  shaft, 
so  that  when  one  bucket  is  descending,  the  other  is  as- 
cending. As  the  shaft  becomes  deeper,  greater  force  is 
required,  and  horse,  steam  or  water-power  is  resorted  to. 

The  machine  employed  for  this  purpose,  is  called  a 
whim,  and  is  simply  the  original  windlass  enlarged  and 
set  on  end.  It  consists  of  an  upright  post  turning  in  a 
socket  at  its  lower,  and  in  a  beam  at  its  upper  extremity ; 
a  cage  or  drum,  round  which  the  rope  is  wound ;  and  a 
pair  of  long  arms,  which  correspond  to  the  handle  of 
the  windlass.  The  beam  in  which  the  upper  end  of  the 
axle  turns,  is  supported  by  strong  timbers  firmly  planted 
in  the  ground  and  strengthened  by  braces.  In  order  to 
convert  the  horizontal  motion  of  the  rope  around  the 
drum,  into  a  vertical  motion  in  the  pit,  the  ropes  are 
passed  over  pulleys  set  in  a  frame  work  erected  over  the 
mouth  of  the  shaft.  The  power  is  of  course  applied  to 
the  extremities  of  the  arms.  Steam  is  only  used  for 
shafts  over  two  hundred  feet  in  depth,  after  the  value  of 
the  mine  has  become  fully  established.  In  this  country, 
small  horizontal  high-pressure  engines  are  usually  em- 
ployed ;  in  Cornwall  the  low-pressure  engine  is  pre- 
ferred. 

As  the  upper  part  of  the  shaft  is  exposed  to  all  the 
changes  of  temperature  of  the  surface,  the  rock  will  be 
liable  to  crumble  and  fall  in.  In  order  to  avoid  this,  it 
is  necessary  to  protect  the  walls  of  the  opening  with 
some  sort  of  covering.  For  this  purpose,  timber  is  gen- 
erally used,  though  sometimes  its  place  is  supplied  by 
masonry.  It  is  stripped  of  its  bark,  as  that,  by  absorb- 
ing and  retaining  moisture,  accelerates  the  decomposi- 


MINES  AND  MINING.  177 

tion  of  the  wood.  With  this  exception  it  is  as  little 
dressed  as  possible.  Resinous  woods,  such  as  pine,  are 
much  less  durable  than  the  harder  varieties. 

A  second  shaft  is  now  to  be  sunk  at  a  suitable  distance 
from  the  first,  and  the  two  are  to  be  connected  by  a  gal- 
lery, usually  termed  a  drift  or  level.  The  distance  of 
these  shafts  varies  with  the  nature  of  the  surface,  the 
richness  of  the  vein,  and  the  depth  of  it  which  can  be 
worked.  A  hundred  yards  has  been  stated  to  be  the 
average  distance  between  two  shafts  in  a  vein  of  moder- 
ate width  and  richness. 

The  shafts  being  steadily  prolonged  downward,  the 
mass  of  the  vein  is  cut  up  into  a  series  of  parallelopipe- 
dons,  by  levels  driven  through  it  and  following  its  direc- 
tion. If  the  shafts  are  at  too  great  distance  apart  for 
the  convenience  of  working,  the  levels  are  connected  by 
shallow  shafts,  called  winzes.  The  usual  perpendicular 
distance  between  the  levels  is  ten  fathoms  or  sixty  feet, 
reckoning  from  the  floor  of  the  upper  to  the  roof  of  the 
lower  level.  The  customary  dimensions  of  these  galle- 
ries are  six  feet  in  height  by  three  in  breadth.  By 
these  the  mine  is  fully  opened,  and  if  they  are  driven 
upon  the  vein,  ore  is  continually  being  taken  out,  so 
that  if  the  lode  is  tolerably  rich,  the  expenses  of  the 
opening  are  more  than  defrayed.  Sometimes  it  is  con- 
venient to  drive  the  levels  by  the  side  of  the  vein,  in 
which  case,  the  wall  is  broken  through  from  time  to 
time. 

The  masses  thus  marked  out  are  removed  by  sloping 
or  working  in  steps,  the  object  of  which  is  to  remove  all 
the  rock  of  the  vein  that  is  worth  taking  down.  There 


178  MINES  AND  MINING. 

are  two  methods  of  doing  this,  known  as  underhand  and 
overhand  stoping. 

If  it  be  determined  to  proceed  by  the  first  plan,  a 
scaffold  is  erected  in  the  shaft,  six  feet  below  the  floor 
of  the  upper  level,  and  the  workman  begins  to  take  out 
the  mass  between  that  floor  and  the  scaffold.  As  he 
advances,  he  fixes  in  the  walls  of  the  cavity,  strong  tim- 
bers, called  stulls,  upon  which  he  lays  a  floor  of  plank 
for  the  reception  of  his  debris.  It  is  necessary  that 
these  should  be  very  strong,  as  they  have  to  support  a 
great  superincumbent  weight  of  fragments  of  rock.  As 
soon  as  the  first  workman  has  cut  away  a  block  six  feet 
high,  three  wide,  and  six  or  eight  long,  another  is  set  to 
work  on  a  scaffold  six  feet  below  him,  and  when  he  has 
penetrated  a  like  distance,  a  third  attacks  the  rock  six 
feet  lower  yet,  and  so  on  till  the  roof  of  the  lower  level 
is  reached.  In  this  way  the  working  resembles  a  series 
of  gigantic  steps,  each  workman  being  six  or  eight  feet 
in  advance  of  the  one  next  below  him. 

If  the  second  plan,  or  overhand  stoping,  be  resolved 
on,  a  scaffold  is  erected  in  the  shaft,  on  a  line  with  the 
roof  of  the  lower  level.  A  workman  placed  upon  this, 
commences  to  cut  away  the  rock  at  the  re-entering  angle 
made  by  the  wall  of  the  shaft  and  the  roof  of  the  level. 
He  constructs  a  floor  in  the  same  manner  as  in  under- 
hand stoping.  When  lie  has  advanced  six  or  eight  feet 
and  removed  all  the  ore  six  feet  above  the  floor  he  has 
constructed,  another  is  set  to  work  six  feet  above  him, 
and  so  on  until  the  floor  of  the  upper  level  is  reached. 
It  will  be  perceived  that  this  method  is  the  very  reverse 
of  the  last,  so  that  the  men  appear  to  be  working  un- 


MINES  AND  MINING.  179 

derneath  a  great  staircase,  instead  of  on  the  face  of  its 


Each  mode  has  its  advantages.  The  former  enables 
the  workman  to  stand  upon  the  body  of  the  vein  itself, 
with  his  work  before  him,  and  not  liable  to  be  injured 
by  splinters  from  the  roof ;  but  he  is  also  compelled  to 
employ  an  enormous  amount  of  timber  to  sustain  the 
rubbish.  The  latter  plan,  with  the  exception  of  the  oc- 
casional discomfort  of  his  attitude  is  the  easiest  for  the 
miner,  as  the  separation  of  the  ore  is  aided  by  the  force 
of  gravity.  The  amount  of  timber  employed  in  this 
method  is  less  than  in  the  former,  but  the  sorting  of  the 
ore  is  more  difficult,  because  the  rich  ore  is  apt  to  be 
covered  with  the  heap  of  rubbish  among  which  it  falls. 

It  is  not  necessary  to  enter  into  a  description  of  the 
miner's  implements,  the  picks,  sledges,  &c.,  or  to  take 
up  space  in  describing  the  operation  of  blasting,  as  all 
this  must  be  familiar  to  our  readers.  We  may  say,  how- 
ever, that  water  need  not  deter  the  novice  in  mining 
operations  from  using  gunpowder.  All  he  has  to  do,  if 
he  cannot  dry  the  cavity,  is  to  secure  his  powder  in  a  tin 
case,  or  in  a  cartridge  bag  rendered  impervious  to 
water. 

It  sometimes  happens  that  the  rock  is  so  extremely 
hard,  that  the  ordinary  tools  produce  little  or  no  im- 
pression on  it.  This  is  the  case  in  the  Rammelsberg, 
where  the  vein  is  large  and  rich,  but  exceedingly  diffi- 
cult to  work.  To  give  an  idea  of  its  hardness,  Dr.  Ure 
relates  an  experiment  tried  there  in  1808.  A  man  set 
to  work  to  bore  a  hole  for  blasting.  He  labored  assidu- 
ously during  11  posts,  of  8  hours  each,  in  all  88  hours, 


180  MINES  AND  MINING. 

without  being  able  to  get  deeper  than  four  inches.  In 
accomplishing  this,  he  wore  out  126  bores,  dulled  26 
others,  which  had  been  retipped  with  steel,  and  201 
which  had  been  sharpened,  besides  consuming  6£  pounds 
of  oil  to  give  him  light,  and  half  a  pound  of  gunpowder 
for  the  blast. 

In  cases  of  this  kind,  fire  is  employed  to  destroy  the 
cohesion  of  the  masses  to  be  wrought.  At  the  Ram- 
melsberg,  this  agent  is  usually  brought  to  bear  upon  the 
roof  of  the  vault.  Piles  of  faggots  are  so  arranged 
throughout  the  galleries,  that  the  top  of  each  shall  not 
be  more  than  two  yards  from  the  roof  of  the  vault. 
This  having  been  attended  to,  together  with  the  other 
work  of  the  mine,  during  the  week,  the  fire  is  kindled 
on  Saturday.  At  4  o'clock,  in  the  morning,  the  fires 
are  lighted,  the  fireman  beginning  in  the  upper  ranges 
so  that  the  vapors  from  below  cannot  stifle  the  newly 
made  fire.  He  descends  from  level  to  level,  kindling 
the  pile  throughout  the  mine,  and  does  not  get  through 
his  work  till  3  o'clock  in  the  afternoon.  Sulphur  and 
arsenic  are  burned  off,  loud  detonations  occur  in  the 
vaults,  and  some  splinters  of  ore  fall,  though  most  of 
the  heated  mineral  retains  its  place  on  the  roof.  The 
fire  is  left  to  itself  till  Monday  morning,  when  a  man 
again  descends  and  extinguishes  such  of  the  fires  as 
have  not  gone  out.  Should  the  action  of  the  former 
piles  be  incomplete,  new  ones  are  built  in  the  same  spots, 
after  the  miners  have  stopped  work  for  the  day.  On 
Tuesday,  all  hands  are  at  work,  detaching  the  friable 
mineral  from  the  roof  with  long  iron  forks,  and  prepar- 
ing new  piles'  to  be  kindled  again  on  Saturday. 


MINES  AND  MINING.  181 

All  these  workings  which  we  have  described,  require 
a  support  of  some  kind.  In  some  cases,  the  rock  is  so 
friable  that  it  is  impossible  to  advance  at  all  without  at- 
tending to  this  before  the  excavations  are  made.  These 
supports  are  either  of  timber  or  of  masonry.  The  for- 
mer is  more  frequently  adopted ;  in  this  country  it  is 
exclusively  employed. 

To  timber  with  complete  frames,  is  to  construct  a  sort 
of  gallery  of  logs  within  the  excavation.  A  floor  piece 
or  sole  is  laid,  on  which  rest  upright  posts,  inclining  a 
little  towards  each  other,  so  as  to  make  the  ceiling  nar- 
rower than  the  floor.  A  cap  is  now  put  on  the  stand- 
ards, and  they  are  morticed  into  it  so  that  they  cannot 
possibly  approach  nearer  to  each  other.  When  the  rock 
is  very  friable,  facing  boards,  which  are  planks,  or  spars 
of  cleft  wood,  are  placed  horizontally  behind  these 
beams,  both  on  the  roof  and  on  the  sides.  The  size  of 
the  timber  and  the  distance  between  the  stanchions  de- 
pend entirely  upon  the  pressure  to  be  resisted.  When 
the  floor  is  sufficiently  solid,  the  uprights  rest  directly 
upon  the  rock.  Sometimes  only  one  side  requires  tim- 
bering, the  other  being  sufficiently  firm.  In  that  case, 
pillars  are  set  up  only  on  one  side ;  on  the  other,  the 
joists  rest  in  holes  cut  in  the  rock.  It  may  happen  that 
the  roof  alone  requires  support.  Then  the  timbers  are 
simply  laid  across  the  top,  being  secured  at  both  ends  in 
sockets  cut  in  the  rock. 

When  masonry  is  employed,  it  is  almost  always  arch- 
ed. Sometimes  when  the  floor  also  requires  attention, 
it  is  built  in  the  form  of  an  ellipse,  like  an  egg-drain. 

The  processes  of  blasting,  the  combustion  of  the  can- 
16 


182  MINES  AND  MINING. 

dies  and  lamps,  as  well  as  the  respiration  of  the  work- 
men, must  soon  thoroughly  contaminate  the  atmosphere 
of  the  narrow  underground  passages  we  have  heen  de- 
scribing. The  emanations  from  the  mine  itself,  result- 
ing from  the  decay  of  wood,  the  decomposition  of  mine- 
rals, the  occasional  evolution  of  arsenical  and  mercurial 
vapors,  all  contribute  to  the  same  results.  It  is  there- 
fore absolutely  necessary  to  secure  such  a  current 
through  the  various  openings  as  shall  sweep  out  these 
poisonous  vapors,  and  furnish  the  workmen  a  sufficient 
amount  of  pure  air  for  respiration.  Numerous  contri- 
vances have  been  resorted  to  for  the  accomplishment  of 
this  necessary  object.  Very  often  it  is  effected  by  mere- 
ly arranging  the  openings  of  two  shafts  at  different  ele- 
vations externally.  The  column  of  air  within  the  mine, 
being  lighter  in  winter  and  heavier  in  summer  than  that 
without,  the  air  naturally  flows  out  of  the  higher  eleva- 
tion in  the  former  season,  and  the  lower  in  the  latter. 
In  long  galleries  two  compartments  are  sometimes  made, 
the  one  larger  than  the  other.  In  the  smaller,  the  air 
sooner  comes  to  the  temperature  of  the  rock,  and  this 
difference  between  the  two  compartments  is  sufficient  to 
establish  a  current.  These  currents  are  often  obtained 
by  raising  a  chimney  sixty  feet  high  over  one  of  the 
shafts,  which  has  the  same  effect  as  sinking  shafts  at 
different  external  levels.  There  are  also  more  complex 
contrivances  for  pumping  the  foul  air  or  forcing  the 
pure  air  in,  which  our  space  will  not  permit  us  to  de- 
scribe. 

The  ore  which  is  separated  with  the  vein-stone   in 
mines,  is  rarely  sufficiently  charged  with  metal  to  be 


MINES  AND  MINING.  183 

merchantable  without  some  preliminary  dressing.  The 
methods  of  concentrating  the  ore  will  now  demand  our 
attention. 

As  the  ores  are  but  sparingly  diffused  through  the 
vein,  being  mixed  with  a  great  quantity  of  stone,  it  is 
the  miner's  duty  to  make  a  preliminary  sorting  of  them 
before  sending  them  up  to  the  surface.  He  separates 
those  which  seem  to  contain  no  metallic  matter,  from 
those  which  have  ore  diffused  through  them.  The  for- 
mer are  allowed  to  remain  in  the  mine,  where  they  are 
used  for  filling  up  in  part,  the  cavities  made  by  the  pro- 
gress of  the  excavations. 

When  the  ores  selected  by  the  miner  reach  the  sur- 
face, they  undergo  a  second  sorting  by  hand.  The  vari- 
ous pieces  are  broken  up  by  hammers  into  small  frag- 
ments, and  are  usually  divided  into  three  varieties :  1st, 
The  gangue  or  stony  matter,  which  is  thrown  away;  2nd, 
The  rich  ore  which  may  be  sent  directly  to  market;  and 
3rd,  The  fragments  which,  containing  little  ore,  are  to 
be  sent  to  the  stamps  or  rolls  for  further  dressing. 

The  latter,  in  order  to  undergo  the  final  separation  of 
ore  from  dead  rock,  must  first  be  reduced  to  the  proper 
degree  of  fineness.  For  this  purpose,  they  are  subject- 
ed to  the  action  of  machinery.  One  of-  the  most  com- 
mon forms  is  a  crusher,  an  apparatus  composed  essen- 
tially of  two  iron  rollers  revolving  in  opposite  direc- 
tions, worked  by  either  steam  or  water-power.  Their 
bearings  are  so  arranged  as  to  slide  in  grooves,  and  con- 
sequently, to  allow  the  cylinders  to  be  brought  closer 
together,  or  to  be  separated  to  a  greater  distance.  To 
prevent  accidents  from  the  sudden  jar  given  to  the  ma- 


184  MINES  AND  MINING. 

chinery  by  the  harder  pieces  of  stone,  a  lever  is  attach- 
ed to  a  sliding  bar  and  shoulder,  so  that  its  outer  extre- 
mity when  loaded  by  a  suitable  weight,  will  keep  the 
rollers  in  sufficiently  close  apposition.  When  a  frag- 
ment, so  hard  as  to  endanger  the  apparatus,  becomes 
entangled  between  the  rollers,  the  weight  rises,  the  jaws 
open  and  allow  the  piece  to  drop.  The  ore  to  be  crush- 
ed is  gradually  let  fall  between  the  two  rollers  from  a 
hopper,  and,  as  it  passes  through,  is  received  into  a 
cylindrical  sieve,  inclined  towards  the  horizon.  This,  be- 
ing agitated  by  the  same  power  which  moves  the  roll- 
ers, allows  a  portion  to  pass  through  upon  the  floor, 
while  the  rest,  being  too  large  for  its  meshes,  falls  into 
the  buckets  of  an  endless  chain  which  carry  it  up  to  the 
level  of  the  hopper,  when  it  is  again  passed  through. 

In  some  cases  a  stamping-mill  is  preferred  to  a  crush- 
er. In  this  apparatus,  a  long  horizontal  axle  is  set  in 
motion  by  steam  or  water-power.  This  axle  is  provided 
with  a  series  of  cams  arranged  in  spirals  round  its  cir- 
cumference. Yertical  wooden  beams  shod  with  heavy 
pieces  of  iron,  are  provided  with  tongues  so  as  to  be 
caught  and  lifted  by  the  cams  during  the  revolution  of 
the  axle.  The  tongues  and  cams  are  so  arranged  as 
to  enable  each  iron  shoe  to  give  three  blows  during  one 
revolution  of  the  axle,  in  a  constant  succession,  so  that 
when  one  beam  is  falling,  the  beam  next  it  is  rising. 
The  iron  shoes  fall  upon  the  mineral  contained  in  a 
large  trough.  This  trough  is  provided  with  several 
openings,  which  have  over  them  a  grating  of  perforated 
sheet-iron.  A  small  stream  of  water  passes  through  the 
arrangement,  sweeping  out,  through  the  holes  of  the 


MINES  AND  MINING.  185 

grating,  those  fragments  of  ore  which  are  sufficiently 
pulverized.  They  are  received  in  a  pit  prepared  for  that 
purpose. 

The  size  of  the  stamp-heads  varies  with  the  nature  of 
the  mineral  to  be  broken.  Their  average  weight  in 
England,  is  from  three  to  four  hundred  pounds.  The 
heads  are  attached  to  the  lifters  by  a  wrought  iron 
shank,  which  is  let  into  the  end  of  the  liftier,  and  made 
fast  by  shrinking  over  it  two  bands  of  iron. 

The  ores  thus  comminuted  are  usually  concentrated 
by  washing.  The  principles  upon  which  this  process 
depends  are  very  simple.  If,  for  example,  a  number  of 
substances  varying  in  form,  size  and  density,  be  swept 
along  by  a  current  of  water,  or  allowed  merely  to  fall 
through  water,  they  will  arrange  themselves  in  accord- 
ance with  the  resistance  or  the  impulse  they  experience 
from  the  fluid.  If  they  are  alike  in  form  and  size,  but 
vary  in  density,  they  will  after  falling  through  water, 
arrange  themselves  in  the  order  of  their  specific  gravi- 
ties, the  heaviest  being  at  the  bottom,  the  lightest  on 
top  of  the  series  of  strata.  If  their  form  and  density 
be  the  same,  but  their  size  different,  the  largest  particles, 
moving  more  rapidly  than  the  others,  will  of  course  ar- 
rive first  at  the  bottom,  and  must  necessarily  occupy  the 
lowest  layer  of  the  sediment.  The  reason  for  this  is  to 
be  found  in  the  fact,  that  though  their  volume  increases 
as  the  product  of  their  three  dimensions,  the  surface 
exposed  to  the  resistance  of  the  water  increases  only  as 
the  product  of  two  of  these  dimensions,  so  that  the  re- 
sistance is  less  in  proportion  in  the  larger  pieces.  If 
the  pieces  have  the  same  volume  and  density,  but  differ 
16* 


186  MINES  AND  MINING. 

as  to  surface,  (which  of  course  involves  a  difference  of 
form,)  it  will  be  found  that  those  which  possess  the  great- 
est surface,  being  most  resisted,  fall  slowest  and  form  the 
upper  layer. 

From  these  considerations,  it  is  evident  that  the  ores 
to  be  dressed,  should  be,  as  nearly  as  possible,  of  the 
same  size,  as  then  they  will  subside  in  the  order  of  their 
specific  gravities,  which  is  what  the  miner  desires.  Prac- 
tically, this  is  effected  by  the  use  of  sieves,  which  classi- 
fy the  pounded  materials  as  to  size.  Their  form  is  of 
course,  beyond  the  control  of  art,  and  this  interferes  to 
a  slight  extent  with  the  result. 

It  is  evident  that  there  are  but  three  classes  to  which 
the  broken  fragments  can  belong.  They  must  either  be 
composed  of  the  ore  exclusively,  of  the  non-metallic 
minerals  exclusively,  or  of  a  mixture  of  the  two.  In 
the  process  of  washing,  the  pure  ore  sinks  to  the  bot- 
tom, the  mixed  ore  comes  next  above  it,  while  the  top 
layer  is  composed  of  the  non-metallic  substances. 

One  of  the  most  ancient  methods  of  employing  water 
for  the  purpose  of  classifying  ores,  was  the  use  of  the 
hand  sieve.  This  is  a  cylinder  closed  at  the  bottom  by 
a  perforated  sheet  of  copper.  The  miner  fills  it  with 
the  mineral  he  wishes  to  operate  upon,  introduces  it 
into  a  large  tub  of  water,  and  works  it  with  a  sort  of 
undulatory  motion.  The  water  streaming  up  through 
the  holes  in  the  bottom,  offers  a  variable  resistance 
to  the  different  substances  in  the  sieve  ;  so  that  the 
heavier  or  richer  particles  sink  to  the  bottom,  and  the 
more  earthly  matters  accumulate  on  the  surface.  These 
the  miner  scrapes  off  with  a  piece  of  thin  iron,  or  with 


MINES  AND  MINING.  187 

his  hand,  and  repeats  the  operation,  as  long  as  the  sur- 
face pieces  continue  poor.  These  are  not  all  rejected; 
those  which  are  considered  metalliferous  enough  to  pay 
for  a  second  sorting  being  laid  aside  for  further  treat- 
ment. That  which  accumulates  at  the  bottom  is  taken 
out  and  sent  to  market.  This  process  is  called  jigging 
or  sieve  washing. 

On  the  Continent  of  Europe,  a  modification  of  this 
method  has  been  generally  adopted.  To  a  beam,  one 
end  of  which  carries  a  box  which  is  filled  with  stones  to 
act  as  a  counterpoise,  is  attached  by  means  of  a  rod,  a 
sieve  resembing  that  used  in  washing  by  hand.  This 
rod  is  fastened  to  the  beam  midway  between  the  turning 
pivot  and  the  end,  which  carries  another  rod  swung 
on  a  pivot.  This  is  worked  up  and  down  in  a  cylinder, 
and  communicates  a  plunging  motion  to  the  sieve.  The 
process  is  precisely  the  same  as  in  hand  washing.  For 
the  sake  of  convenience  a  table  is  placed  near  the  deep 
tub  to  receive  the  ores. 

In  Cornwall,  copper  ores  are  washed  by  a  much  better 
and  larger  apparatus.  "  This  consists  of  a  large  box,  cover- 
ed with  a  tight  wooden  floor,  in  the  centre  of  which,  is  a 
circular  metallic  trough,  perforated  with  six  holes,  each 
about  two  feet  in  diameter,  and  into  all  these  openings 
a  sieve  is  closely  fitted.  A  large  piston  working  in  a 
cylinder  placed  in  the  centre  of  this  arrangement,  and 
which  is  moved  by  an  eccentric,  driven  either  by  water 
or  steam  power,  is  made  to  alternately  raise  and  depress 
the  level  of  the  water  in  the  box  and  consequently 
also  in  the  sieves,  which  are  fixed  water-tight  into  the 
rings  on  the  top  of  it.  By  this  motion  of  the  water,  the 


188  MINES  AND  MINING. 

particles  of  minerals  contained  in  the  sieves  are 
made  to  arrange  themselves  according  to  their  several 
densities,  and  when  it  becomes  necessary  to  remove  a 
sieve  from  its  place  for  the  purpose  of  scraping  off  the 
less  valuable  and  lighter  portion  of  its  contents ;  its 
place  is  supplied  by  another,  which  is  kept  ready  filled 
to  occupy  the  same  ring  when  required." 

"  Of  the  portions  which  are  scraped  off  from  the  sur- 
face of  the  sieve,  the  lightest  contains  little  or  no  metalic 
ore  and  is  thrown  away ;  but  the  second,  consisting  of  a 
mixture  of  gangue  and  metalliferous  substances,  together 
with  the  finely  divided  dust  which  passes  through  the 
holes  of  the  sieve,  is  sent  to  the  stamping  mill,  where  it 
is  reduced  to  the  state  of  much  finer  powder,  by  which 
treatment  greater  facilities  are  afforded  for  its  separa- 
tion from  earthy  impurities.  When  the  ores  are  not 
stamped  dry,  the  water  and  work  (fine  sand)  escaping 
through  the  gratings  of  the  machine  are  conducted  into 
a  sort  of  reservoir,  where  the  heavier  particles  are  first 
deposited,  and  the  poor  and  consequently  lighter  parts, 
are  removed  to  a  greater  distance.  By  this  process,  a 
certain  classification  of  the  work  is  effected,  as  those 
portions  which  have  been  carried  by  the  force  of  the 
water  beyond  a  given  point,  are  collected  in  a  separate 
basin  from  those  which  have  not  arrived  so  far  from  the 
stamping-mill."  * 

The  arrangements  for  washing  the  finely  pulverized 
ores,  varies  in  different  places,  and  with  different  ores. 

The  G-erman  chest  is  a  long  box  placed  in  a  slightly 
inclined  position,  and  having  in  its  lower  end,  a  series 

*  Phillips'  Metallurgy,  p.  113. 


MINES  AND  MINING.  189 

of  holes,  closed  with  wooden  pegs.  At  the  higher  end, 
a  platform  is  placed  to  contain  the  ores,  over  which 
plays  a  small  stream  of  water.  This  carries  off  in  sus- 
pension the  finer  particles  of  the  ore  and,  deposits  them 
at  distances  varying  inversely  as  their  specific  gravity. 
As  soon  as  the  box  is  full  of  water,  the  stream  is  stopped, 
and  the  lower  peg  being  withdrawn,  the  water  and  fine 
powder  are  allowed  to  flow  off  into  reservoirs,  where  the 
solid  matter  subsides.  As  the  chest  becomes  gradually 
filled  with  the  deposited  sand,  peg  after  peg  is  withdrawn, 
till  at  last,  when  quite  full,  the  uppermost  peg  is  taken 
out.  The  heaviest  ore  is  found  to  be  deposited  near  the 
head  of  the  pit,  and  the  others  distributed  in  the  order 
of  their  richness,  at  varying  distances.  The  first  is 
ready  for  smelting,  the  other  portions  require  further 
treatment. 

The  sleeping  or  twin  tables  are  two  inclined  planes, 
about  twenty-five  feet  long,  placed  side  by  side,  and 
provided  with  ledges  to  prevent  the  ore  from  running  off 
at  the  sides.  At  their  upper  extremities,  is  an  appara- 
tus, worked  by  a  small  water-wheel,  for  thoroughly  in- 
corporating the  fine  ore  with  water.  Thus  mingled,  it  is 
introduced  on  the  upper  part  of  the  planes,  and  a  stream 
of  water  allowed  to  flow  over  it.  This  separates  the 
different  substances  in  the  order  of  their  densities,  the 
lighter  being  swept  off  by  the  current.  The  workman 
accelerates  this  process  of  separation,  by  sweeping  the 
ore  up  the  planes  with  a  small  broom,  until  he  is  satisfied 
that  the  ore  is  fully  concentrated,  when  it  is  suffered  to 
fall  through  an  opening  near  the  lower  end  of  the  plane, 
into  receptacles  prepared  for  it.  The  inclination  given 


190  MINES  AND  MINING. 

to  these  tables  varies  with  the  fineness  of  the  powder 
they  are  expected  to  sort,  being  greater  the  coarser  the 
grains. 

The  percussion  table  is  also  an  inclined  plane,  but  it 
is  swung  by  chains,  which  at  the  upper  extremity,  at- 
tach it  to  fixed  beams,  at  the  lower  to  a  moveable  lever, 
cams  on  the  axle  of  a  water-wheel,  strike  on  an  upright 
connected  with  the  table,  and  subject  it  to  repeated  con- 
cussions. The  ore  is  mixed  with  water  and  allowed  to 
flow  over  the  surface,  as  in  the  last  described  apparatus, 
but  the  repeated  jars,  assist  in  the  separation  of  the 
light  from  the  heavier  particles,  so  that  the  apparatus 
is,  in  principle,  a  sort  of  combination  of  the  sleeping 
table  and  the  jigging  machine. 

In  Cornwall  buddies  and  racks  are  used  instead  of  the 
tables. 

The  nicking -buddle  is  a  long  inclined  trough,  or  cis- 
tern, resembling  a  German  chest.  At  its  head  is  an 
inclined  shelf,  higher  than  the  floor  of  the  cistern, 
terminated  above  by  a  wooden  head-board,  provided 
with  an  opening  closed-  by  a  plug,  which  regulates  the 
admission  of  water  from  a  little  dam  behind  it.  The 
ore  having  been  placed  on  the  higher  shelf,  a  stream  of 
water  is  let  on,  meanwhile  a  boy  stationed  in  the  pit, 
alternately  smooths  and  notches  the  layer  of  ore,  with 
a  sharp  shovel.  The  ore  is  soon  washed  from  the  head, 
and  when  it  has  fallen  in  the  body  of  the  apparatus,  the 
boy  continually  sweeps  it  back  towards  the  head  again. 
This  facilitates  the  separation  of  the  light  from  the  heavy 
particles,  the  former  being  carried  down  towards  the 
bottom  of  the  buddle.  When  the  deposit  of  heavy  par- 


MINES  AND  MINING.  191 

tides  has  sufficiently  filled  the  cistern,  the  light  gangue, 
suspended  in  the  water,  is  drawn  off.  The  heavy  sand 
is  drained,  and  divided  into  three  portions  according  to 
its  richness.  The  ore  nearest  the  head  of  the  huddle  is 
usually  rich  enough  to  be  smelted ;  that  next  to  it  is  laid 
aside  for  a  second  puddling,  while  the  lowest  and  light- 
est is  sent  to  the  rack. 

The  rack  consists  of  a  smooth  wooden  flooring,  with 
strong  ledges  around  it,  inclined  to  the  horizon,  and 
provided,  like  the  huddle  with  an  upper  shelf  and  head- 
board. It  rests  upon  pivots,  so  as  to  enable  the  work- 
man, when  desirable  to  turn  it  on  the  pivots.  The  water 
is  let  on  to  the  lower  level  over  a  flap,  swung  on  leather 
hinges. 

The  ore  is  laid  on  the  higher  shelf,  and  alternately 
grooved  and  flattened  by  means  of  a  wooden  hoe.  The 
water  carries  it  down  to  the  lower  level,  where  it  is 
moved  by  a  rake  to  the  highest  point  of  the  arrangement, 
the  water  flowing  continually  over  it.  A  small  broom 
is  also  used  to  complete  the  washing,  the  earthy  matter 
being  suffered  to  flow  out  into  reservoirs  prepared  for 
its  reception. 

When  a  sufficient  layer  of  mineral  has  by  this  manip- 
ulation been  collected  on  the  table,  it  is  made  to  take 
a  quarter  revolution  on  its  axis,  and  when  in  a  vertical 
position,  is  caught  by  a  wooden  spring,  which  holds  it 
firmly  in  that  situation. 

The  person  working  the  frame,  now  washes  off  the  ore 
by  the  use  of  a  wooden  bowl  with  a  long  handle,  which 
causes  it  to  fall  first  into  the  angle,  formed  by  the 
meeting  of  one  of  the  sides  with  the  floor,  and  alternately 


192  MINES  AND  MINING. 

into  boxes  placed  beneath  for  its  reception.  In  this, 
as  in  the  preceding  examples,  the  richer  ore  will  be 
found  to  accumulate  at  the  upper  end  of  the  inclined 
plane,  and  therefore  the  washed  ore  is  divided  into  two 
parts,  each  of  which  falls  into  a  different  receptacle. 

"  This  division  is  made  by  a  fillet,  placed  on  the  side 
of  the  rack  at  about  equal  distances  from  its  two  extre- 
mities, and  which,  when  the  plane  is  brought  in  a  pro- 
per position  for  washing  off  the  deposited  metalliferous 
grains,  forms  a  dam,  and  causes  that  which  is  deposited 
in  the  upper  part  of  the  floor  to  fall  into  one  box,  or 
cover,  whilst  that  which  is  deposited  in  the  lower,  falls 
into  another."* 

*  Op.  cit. 


CHAPTER  IV. 

MINES     OF     COPPER. 

COPPER  is  very  widely  distributed  over  the  surface  of 
the  globe,  and  occurs  in  many  geological  formations. 
Often  it  exists  in  mere  detached  minerals,  not  connected 
with  any  great  mass  of  ore,  and  at  others  it  is  so  abun- 
dant that  it  may  be  considered  inexhaustible.  The 
great  mining  districts  have  so  far  been  found  in  two  dis- 
tinct geological  positions ;  first,  in  the  older  crystalline 
rocks,  especially  the  metamorphic  palaeozoic,  and  in  the 
igneous  formations  associated  with  them ;  secondly,  in 
the  strata  lying  between  the  coal  measures  and  the  lias, 
which  is  the  lowest  member  of  the  Jurassic  or  oolitic 
group.  The  best  examples  of  the  former  mode  of  occur- 
rence are  the  mines  of  Cornwall,  Australia  and  Lake 
Superior.  The  veins  are  either  segregated,  or  true  fis- 
sure veins,  the  former  being  sometimes  large  and  pro- 
ductive, but  the  latter  being  more  permanent.  Of  the 
second  mode  of  occurrence,  the  schists  of  Mansfeld, 
and  the  Ural  mines  are  examples.  In  the  new  red 
sandstone  of  our  country,  which  is  usually  referred  to 
the  Triassic  group,  but  lately  classified  among  the  lower 
Oolitic  rocks,  copper  ores  are  also  found.  Above  the 
new  red  sandstone  few  important  deposits  of  copper  have 
been  discovered. 
17 


194  MINES  OF  COPPER. 

EUROPEAN   MINES. 

British  Mines. — Cornwall  is  the  great  district  of  Bri- 
tish mining,  and  as  the  mines  of  that  region  are  usually 
selected  as  a  basis  of  comparison  with  other  deposits,  it 
will  be  well  to  consider  somewhat  carefully  its  geology. 

The  mines  of  Cornwall  occur  either  in  granite  or  the 
schistose  rocks  that  accompany  it.  Of  these,  the  killas* 
or  greenish  argillaceous  slate  and  the  growan  or  granite 
are  the  most  important  for  the  copper  miner.  Porphyry, 
called  by  the  miners,  elvan,  also  occurs,  but  it  is  chiefly 
valuable  for  the  tin  which  it  carries.  The  term  elvan 
is  likewise  applied  generally  to  any  rocky  mass  that  oc- 
curs in  the  slates  and  granites  and  displaces  the  rocks. 
The  porphyry  usually  occurs  in  long  narrow  dykes, 
some  of  the  seams  having  been  traced  for  twelve  miles. 

The  granite  is  found  in  six  great  isolated  masses,  as 
well  as  in  smaller  patches.  The  great  masses  have  a 
general  linear  direction  northeast  and  southwest.  It  is 
remarkable  for  carrying  a  great  deal  of  schorl  or  black 
tourmaline,  which  is  especially  abundant  along  the  con- 
fines of  the  granite  and  slate.  The  latter  rocks  abut 
abruptly  upon  'one  another,  the  only  change  which  is 
noticeable  in  the  killas  being  a  condensation  of  the  mass, 
the  granite  frequently  penetrating  it.  De  la  Beche 
makes  a  distinction  between  the  mica  and  hornblende 
slates,  and  the  grauwacke  group,  a  collection  of  sedi- 
mentary deposits  varying  from  the  finest  roofing  slates 
to  the  coarsest  possible  conglomerates. 

The  same  eminent  geologist  divides  the  mining  dis- 
trict of  Cornwall  and  Devon  into  six  groups ; — 1st.  Tavis- 
*  This  term  is  also  applied  to  slate  in  general. 


MINES  OF  COPPER.  195 

tock,  bearing  copper,  tin,  and  silver  lead;  2d.  St.  Aus- 
tell,  containing  tin;  3d.  St.  Agnes;  4th.  Gwennap, 
Redruth  and  Carnborne,  a  copper  region ;  5th.  Breagin, 
Mazarien  and  Gwinear,  producing  tin,  copper,  lead  and 
silver;  6th.  St.  Just  and  St.  Ives,  bearing  tin  chiefly. 
The  ores  of  copper  and  tin  are  always  found  in  the 
neighborhood  of  the  granite  or  porphyry. 

The  system  of  the  veins  of  this  district  is  exceedingly 
complex.  Mr.  Game's  classification,  adopted  by  Dr. 
Ure,  in  his  Dictionary  of  Arts,  Manufactures  and  Mines, 
is  as  follows ; 

1.  Veins  of  elvan;  elvan  courses,  or  elvan  channels. 

2.  Tin  veins  or  lodes. 

3.  Copper  veins  running  east  and  west;  east  and  west 
copper  lodes. 

4.  Second  system  of  copper  veins,  or  contra  copper 
lodes. 

5.  Modern  copper  veins;  more  recent  copper  lodes. 
7.  Clay  veins,  of  which  there  are  two  sets,  the  more 

ancient  called  cross-fluckans,  the  more  modern  called 
slides. 

These  divisions  appear  to  be  the  result  of  an  analysis 
altogether  too  refined.  Sir  H.  de  la  Beche,  who  paid 
great  attention  to  these  mines,  does  not  attempt  to  assign 
definite  ages  to  the  copper  veins,  so  that  the  third, 
fourth  and  fifth  divisions  in  the  above  table  may  be 
united  in  one.  As  to  the  tin  veins,  they  are  generally 
believed  to  be  older  than  the  copper  lodes,  but  even  this 
idea  may  be  dismissed,  since  it  has  been  ascertained 
that  the  very  same  lode  may  carry  tin  in  one  part  of  its 
course  and  copper  in  another.  The  second  division  of 


196  MINES  OF  COPPER. 

the  table  may  therefore  be  incorporated  with  the  three 
following  it.  We  shall  then  have  three  classes  of 
veins. 

First,  the  elvan  courses,  which  follow  nearly  the  range 
of  the  granite  rocks,  traversing  them,  and  are  them- 
selves cut  by  the  true  productive  lodes. 

Second,  the  great  metalliferous  lodes,  which  have  the 
same  general  direction  with  the  elvans,  but  which  inter- 
sect them  and  consequently  are  more  recent. 

TJiird,  the  cross-courses,  or  veins  and  fissures  which 
run  north  and  south,  cutting  the  east  and  west  lodes  at 
angles  varying  from  seventy  to  ninety  degrees.  They 
carry  argentiferous  lead  in  some  places,  but  are  gene- 
rally barren,  being  filled  with  clay.  Their  date  is  mod- 
ern, being  supposed  to  have  occurred  later  than  the  cre- 
taceous period.  They  are  themselves  occasionally  cut  by 
what  are  called  the  east  and  west  slides. 

Of  these  systems  of  veins,  we  have  only  to  notice  the 
copper  lodes.  '  Near  the  surface,  where  they  have  been 
exposed  to  atmospheric  influences,  they  are  much  decom- 
posed, and  abound  in  gossan.  This  is  a  mixture  of 
quartz  with  more  or  less  oxide  of  iron,  containing  also 
insoluble  combinations  of  other  metals.  The  theory  of 
its  formation  is  simple.  The  vein-stone  with  its  metal- 
lic contents,  having  been  subjected  to  the  influence  of 
oxygen,  has  had  soluble  sulphates  formed  in  it,  which 
have  been  subsequently  leached  out  by  rain  water.  Sul- 
phate of  iron,  decomposing  readily,  leaves  behind  it  the 
hydrated  oxide  of  that  metal  which  gives  its  foxy  red 
color  to  the  mass.  The  less  alterable  minerals,  gold, 
ores  of  silver  and  tin,  remain  behind.  In  the  English 


MINES  OF  COPPER.  197 

gossans,  silver  occasionally  occurs  in  sufficient  quantity 
to  be  worked.  Gold  is  found  in  many  of  them,  to  the 
extent  of  one  or  two  ounces  to  the  ton,  and  tin  has  been 
so  abundant  that  the  gossans  have  been  mined  for  that 
metal.  The  depth  of  this  decomposition  varies  from 
twenty  to  thirty  fathoms.  All  gossans  are  not  equally 
valuable  indications  of  the  presence  of  valuable  mineral 
at  greater  depth,  and  experience  enables  the  miner  to 
form  an  idea  of  the  prospects  of  a  mining  estate,  by  a 
careful  inspection  of  this  overlying  rock. 

The  lodes,  below  the  point  at  which  the  atmosphere 
ceases  to  act,  contain  chiefly  copper  pyrites,  mixed 
with  other  ores  of  copper  and  with  sulphuret  of  zinc. 
The  ores  are  not  uniformly  diffused  through  the  veins, 
but  occur  in  masses  of  variable  size,  connected  by  threads 
and  strings  too  small  to  be  worked  with  advantage,  yet 
distinct  enough  to  be  followed  by  the  miners.  The  width 
of  the  veins  averages  six  feet,  though  enlargements  to 
the  extent  of  twelve  feet  occasionally  occur.  The 
gangue  is  usually  quartz,  often  mixed  with  green  matter 
resembling  chlorite.  The  veins  are  generally  accompa- 
nied by  argillaceous  bands  called  the  fluckan  of  the 
lode. 

The  productiveness  of  the  lodes  vary  with  the  nature 
of  the  "country,"  and  with  the  displacements  to  which 
they  have  been  subjected.  If  they  ramify  as  they 
descend,  the  ore  diminishes;  but  if  the  various  strings 
coalesce  downwards,  the  product  of  ore  increases.  In 
like  manner,  when  different  veins  unite,  the  quantity  of 
ore  usually  increases.  In  the  Gwennap  district,  the 
east  and  west  veins  all  become  productive,  where  the 
IT* 


198  MINES  OP  COPPER. 

great  counter-lode  cuts  them.  As  a  general  rule,  the 
smaller  the  angle  at  which  two  lodes  cross  one  another, 
the  hetter  are  the  prospects  for  a  great  amount  of  ore. 
The  elvan  dykes  have  also  been  found  to  exert  a  very 
beneficial  influence  upon  the  richness  of  the  mine. 
The  nature  of  the  rock  which  the  veins  traverse  also 
affects  the  lode.  The  most  productive  portions  are 
always  in  the  neighborhood  of  the  point  where  the  gran- 
ite meets  the  killas.  No  general  rule  can  be  given  for 
determining  the  productiveness  of  a  lode  in  either  of  these 
rocks,  there  being  great  variation,  in  this  respect,  in 
different  mines.  Thus,  of  two  parallel  tin  lodes,  only  a 
mile  apart,  one  was  unproductive  in  the  slate,  and  rich 
in  the  granite,  while  the  other  was  just  the  reverse. 
The  slates  were  formerly  considered  the  best  "country" 
for  copper,  but  rich  mines  have  been  worked  in  the  gran- 
ite not  very  far  from  its  junction  with  the  killas.  The 
characters  of  the  rock  in  any  formation  seem  to  influ- 
ence the  yield  of  copper.  Thus,  in  the  Gwennap  dis- 
trict, the  red  killas  is  considered  unproductive  and  the 
bluish  gray  variety  alone  is  believed  to  justify  extensive 
working. 

As  to  the  yield  of  a  mine  at  various  depths,  it  has 
been  generally  believed  that  a  true  vein  grows  continu- 
ally richer  as  it  descends.  Some  doubt  has  been  recently 
cast  upon  this  opinion,  from  the  fact  that  in  certain  old 
mines  this  gradual  increase  in  value  stopped  at  a  very 
moderate  depth,  beyond  which  the  metallic  contents  of 
the  vein  remain  stationary,  or,  according  to  some  autho- 
rities, actually  diminish.  It  has  been  asserted  that  the 
results  of  working  prove  that  a  vein,  which  is  poor  at 


MINES  OF  COPPER.  199 

the  surface,  increases  in  richness  to  a  certain  depth, 
where  it  reaches  its  maximum  and  then  diminishes  in 
productiveness,  while  a  lode,  rich  at  the  surface,  contin- 
ues good  for  a  certain  distance  and  then  begins  to  de- 
crease, at  much  less  depth  than  the  poorer  lode.  These 
statements  have  been  denied  on  the  ground  that  some 
of  the  deepest  mines  in  Cornwall  continue  to  furnish 
great  abundance  of  ore.  In  connection  with  this  ques- 
tion, it  must  not  be  forgotten  that  the  time  of  greatest 
prosperity  of  each  mine  has  been  when  its  workings  had 
reached  a  moderate  depth,  a  fact  which  seems  to  show 
that  the  increase  of  ore  in  the  lode  at  the  greater  depths, 
if  it  really  occur,  is  not  sufficient  to  meet  the  augmented 
expense  of  raising  it  from  such  very  deep  levels.  For 
example,  in  1815  the  Dolcoath  mine  was  the  richest; 
in  1817  the  United  mines  stood  first;  in  1822  the  Con- 
solidated mines  gave  the  largest  product,  and  since  1845 
the  Devon  Consols  have  held  the  first  place.  The  deep- 
est mines  have  been  sunk  over  2000  feet. 

It  is  very  important  to  consider  the  dip ;  a  vein  which 
has  an  inclination  varying  much  from  the  perpendicular, 
being  rarely  very  valuable.  In  a  lode  which  often 
changes  its  inclination,  those  portions  which  are  most 
nearly  perpendicular,  are  usually  the  richest. 

These  mines  are  worked  on  a  grand  scale,  and  with 
great  skill.  The  Great  adit  reaches  nearly  five  and  a 
half  miles,  in  a  direct  line  ;  and  if  all  its  ramifications 
be  taken  into  account,  its  length  is  thirty-five  miles.  At 
its  deepest  point,  it  is  seventy  fathoms  below  the  sur- 
face. We  subjoin  a  very  brief  sketch  of  some  of  the 
principal  Cornish  mines. 


200  MINES  OF  COPPER. 

The  Dolcoath  Mine  is  the  oldest  in  Corn-wall,  having 
been  worked  with  little  interruption  for  a  century.  It  is 
three  hundred  fathoms  deep.  It  has  paid  out  £300,000 
in  dividends.  In  the  thirty-six  years  from  1814  to  1848, 
it  furnished  238,059  tons  of  ore,  worth  £1,361,681. 

The  G-reat  Consolidated  Mines  are  very  celebrated. 
In  1848,  the  workings  were  sixty-three  miles  long,  and 
had  made  a  profit  of  £700,000.  From  1819  to  1840, 
these  mines  cleared  £500,000,  besides  expending  £100,- 
000  in  opening  the  United  Mines.  During  the  last 
twelve  months  of  that  period,  they  yielded  17,283  tons 
of  ore,  worth  £100,279.  From  1840  to  1848,  there 
were  taken  out  83,660  tons,  sold  at  £490,543,  of  which, 
owing  to  the  heavy  expense  of  the  workings,  only  £32,- 
000  was  divided  among  the  stockholders.  In  March, 
1854,  no  dividend  having  been  declared  for  more  than 
three  years,  the  price  of  shares  went  down  ninety  per 
cent,  below  par. 

The  Devon  Grreat  Consolidated  Company,  usually 
called  Devon  Consols,  has  made  enormous  profits.  They 
began  in  August,  1844,  with  1024  shares,  at  £1  per 
share,  paid  in.  The  ground  was  leased  of  the  Duke  of 
Bedford  for  twenty-one  years,  at  a  royalty  of  one- 
fifteenth,  to  be  raised  to  one-twelfth  after  £20,000  had 
been  cleared.  The  lode,  at  eighty-four  feet  from  the 
surface,  was  eighteen  feet  wide,  "  carrying  an  immense 
gossan."  At  the  depth  of  one  hundred  and  five  feet,  the 
great  deposit  was  reached.  In  the  first  three  months  of 
regular  working,  the  mine  cleared  over  £15,000  ;  the 
next  year,  1846,  the  profit^  were  £39,590.  By  1850, 
ten  shafts  had  been  sunk  in  the  lode,  the  deepest  having 


MINES  OF  COPPER.  201 

reached  six  hundred  feet,  and  one  thousand  persons 
were  employed  about  the  mine.  Up  to  January,  1853, 
£358  had  been  paid  in  dividends  on  each  share,  and 
the  original  shares  of  <£!  sold  for  .£430.  Up  to  that 
time,  131,141  tons  of  ore  had  been  taken  out  and  sold 
for  £882,742.  In  1854,  the  mine  produced  23,174 
tons.  At  present,  the  mine  pays  dividends  every  two 
months,  and  the  stock  sells  at  £410  per  share. 

During  the  year  1853,  sixty  English  mines  paid  out 
in  dividends  £329,015,  of  which  two,  the  Devon  Consols 
and  the  Wheal  Buller,  paid  £110,464.  At  that  time, 
shares  in  the  latter  mine  on  which  £5  had  been  paid  in, 
were  worth  £1,025. 

The  average  annual  production  of  this  mining  region 
has  steadily  increased  until  the  past  year,  when  it  fell 
somewhat  short.  In  the  Appendix  will  be  found  a  table 
expressing  it.  It  will  there  be  seen  that  the  product 
for  the  year  1853  was  more  than  three  times  greater 
than  the  annual  product  at  the  beginning  of  this  cen- 
tury, but  that  the  percentage  was  one-third  lower.  The 
average  yield  from  1771  to  1786  was  twelve  per  cent. 
of  copper,  that  of  the  first  twelve  years  of  this  century, 
8.95;  of  the  next  twelve,  8.4;  of  the  next  twelve,  8, 
and  of  the  next,  7.7.  In  1853,  the  product  was  only 
6.6,  so  that  although  more  ore  was  sold  than  ever  be- 
fore, and  at  a  higher  rate,  many  years  exceeded  it  in 
the  actual  amount  of  pure  metal  obtained  from  the  ore. 
The  average  of  the  first  three  quarters  of  1856,  was 
6.27,  the  total  produce  being  143,200  tons. 

The  number  of  copper  mines  now  worked  in  England 
is  one  hundred  and  seven,  seven  of  which  are  not  selling 


202  MINES  OF  COPPER. 

ores.  Of  those  which  are  selling,  twenty-six  are  paying 
dividends.  The  entire  amount  of  capital  originally  in- 
vested in  all  the  mines  is  £1,078,092,  on  which  £2,294,- 
478  have  been  paid  in  dividends.  The  annual  dividend 
is  £291,282,  or  one  hundred  and  thirty-four  per  cent, 
on  the  capital  invested  in  dividend-paying  mines.  In 
1854,  the  number  of  mines  was  somewhat  larger. 
Robert  Hunt  says  that  one  hundred  and  eleven  mines 
sold  in  that  year  ores  in  quantities  above  fifty  tons  each. 

France.  There  is  no  copper  mine  of  any  importance 
in  this  country.  Some  time  since,  mines  at  Chessy  and 
Saint  Bel  were  wrought,  but  they  are  now  abandoned. 
The  chief  interest  attaching  to  them  is  to  be  found  in 
the  magnificent  crystals  of  azurite  they  produced. 

Prussia.  Mansfeld  has  long  been  celebrated  as  an 
exception  to  the  ordinary  laws  of  copper-mining.  For 
centuries  a  deposit  having  none  of  the  characteristics  of 
a  regular  vein,  has  been  worked  to  advantage.  The 
cupriferous  rock  is  a  regular  member  of  a  geological  se- 
ries, and  though  not  more  than  two  or  three  feet  thick, 
and  containing  a  very  small  percentage  of  copper,  its 
great  extent  and  extreme  regularity  admit  of  its  being 
profitably  worked.  The  ore  is  gray  copper  containing 
silver,  and  the  rock  which  bears  it  is  a  bituminous  marly 
slate. 

Near  Stadburg,  in  the  district  of  Liegen,  is  a  silicious 
slate  which  contains  numerous  particles  of  carbonate  of 
copper.  These  are  dissolved  out  by  sulphuric  acid,  and 
precipitated  by  metallic  iron. 

Regular  veins  of  copper  also  occur  in  various  parts  of 
the  kingdom.  The  entire  yield  of  the  country  amounted, 
in  1850,  to  1450  tons. 


MINES  OF  COPPER.  203 

Austrian  Empire.  By  far  the  largest  portion  of  the 
copper  produced  by  this  empire  comes  from  its  depen- 
dency Hungary.  In  Lower  Hungary,  at  Schemnitz, 
the  mines  were  formerly  valuable,  but  the  region  is  now 
more  celebrated  for  its  mining  school  than  for  its  pro- 
ductiveness. At  Schrnollnitz,  the  copper  ores  are  argen- 
tiferous, as  they  also  are  in  the  Banat. 

At  Tsiklova,  in  the  Banat,  there  is  an  establishment 
for  smelting  the  ore  and  separating  the  silver  from  the 
copper.  ,The  process  will  be  described  in  the  next 
chapter.  The  ores  of  the  Banat  occur  in  irregular  de- 
posits, near  the  junction  of  the  sienite  with  metamorphic 
Jurassic  rocks.  They  consist  of  copper  pyrites,  with 
gray  copper  carrying  silver,  blende,  iron  pyrites  and  a 
little  gold.  They  do  not  yield  more  than  four  per  cent, 
of  copper  after  sorting  by  hand. 

The  annual  product  of  the  empire  is  a  little  over 
3,300  tons. 

Spain.  The  mines  of  Rio  Tinto  are  the  oldest  in  the 
country,  having  been  worked  by  the  Romans.  The 
water  issuing  from  the  old  workings  is  now  treated  with 
iron,  furnishing  copper  by  cementation.  In  1833,  one 
hundred  and  forty  tons  were  obtained  in  this  way. 
English  companies  are  now  working  the  Linares  mines, 
which  yield  both  lead  and  copper.  The  entire  produce 
of  the  kingdom  for  1849  is  estimated  at  450  tons. 

Italy.  The  Tuscan  mines  are  the  best  known  in 
Italy,  and  they  do  not  produce  much.  The  ores  of 
Monte  Catini  occur  in  contact  deposits,  and,  contrary 
to  the  usual  rule,  grow  richer  as  they  descend. 

Turkey.     This  country  produces  much  good  copper 


204  MINES  OF  COPPER. 

Russian  Empire.  The  most  extensive  mines  are  in 
the  neighborhood  of  the  Ural  Mountains.  On  their 
western  flanks,  in  the  governments  of  Perme  and  Oren- 
burg, the  beds  of  the  Permian  system  are  cupriferous 
and  resemble  the  copper  schists  of  Mansfeld.  The  ores, 
chiefly  malachite,  are  distributed  through  thick,  gray, 
flag-like  grits.  These  contain  only  about  2J  per  cent, 
of  ore,  but  the  beds  are  so  large  that,  even  this  small 
quantity  pays  well  for  extraction.  The  metal  obtained 
from  them  is  of  very  fine  quality,  and  in  great  request 
for  making  bronze.  They  furnish  about  260  tons 
annually,  and  pay  the  government  a  profit  of  about 
$40,000. 

On  the  east  side  of  Ural  Mountains  the  most  valuable 
deposits  occur.  The  principle  mines  are  the  Gum- 
eschewskoi,  the  Bogoslowski  and  those  of  Nijny  Tagilsk. 

At  the  former  place  there  are  no  regular  veins.  The 
mine  has  been  worked  for  more  than  a  hundred  years, 
on  bunches  and  nests  of  copper  ore,  chiefly  malachite 
and  red  oxide,  contained  in  argillaceous  shales.  The 
malachite  is  in  large  masses ;  a  cube,  three  feet  and  a- 
half  in  diameter,  was  taken  from  this  mine. 

The  Tarjinsk  mines  near  Bogoslowski,  occur  in  a  Si- 
lurian limestone,  the  strata  of  which  alternate  with  beds 
or  dykes  of  trap.  Along  the  lines  of  contact  occur  de- 
posits of  clay,  in  which  the  copper  ores  are  found  in 
bunches  and  nests.  Fine  crystals  of  native  copper 
occur  here. 

At  Nijny  Tagilsk,  the  ore  lies  in  hollows  of  the  erup- 
tive works,  and  is  mixed  up  with  lumps  of  limestone  and 
and  other  rocks.  At  the  depth  of  280  feet  there  was 


MINES  OF  COPPER.  205 

discovered  a  mass  of  malachite,  estimated  to  weigh  over 
580  tons. 

The  average  annual  product  of  the  Ural  mines  during 
the  ten  years  preceding  1848,  was  3720  tons  of  copper. 
In  1850  it  exceeded  5400  tons. 

There  are  other  mines  in  the  Caucasus,  in  the  Altai 
and  in  Finland.  Those  of  the  Caucasus  contain  much 
ore  and  give  evidences  of  having  been  extensively 
worked  long  since.  The  mines  of  Altai  yield  an  annual 
product  of  400  or  500  tons. 

The  average  annual  amount  of  copper  produced  by 
Russia,  has  been  4,540  tons.  It  is  on  the  increase.  In 
1849  it  was  6,546,  and  in  1850,  6,449  tons.  But  little 
is  exported. 

Norway  and  Sweden.  There  is  not  a  very  great 
amount  of  copper  produced  by  this  northern  Peninsula. 
That  obtained  in  Norway  is  reputed  better  than  that 
from  the  Swedish  mines. 

The  mines  of  Alten,  in  Norway,  latitude  70°,  are  the 
most  northern  in  the  world.  They  have  been  worked 
by  an  English  Company  since  1826 ;  the  formation  in 
which  they  occur  belongs  to  the  metamorphic  palaeozoic 
or  azoic,  with  which  are  associated  diorite  and 
hornblende.  At  Kaafjord,  the  ores  occur  in  igneous 
rocks  cutting  slates.  In  the  former  alone  they  are  pro- 
ductive, often,  indeed  they  disappear  entirely  in  the 
slates.  On  the  Raipasvara  Mountains,  a  few  miles  from 
the  last  named  locality,  another  group  of  copper  lodes 
occurs  in  compact  subcrystalline  limestone,  intercalated 
with  slates.  The  principal  vein  is  six  feet  wide,  dips 
vertically,  and  contains  near  the  surface,  gossan  with  car- 
18 


206  MINES  OF  COPPEK. 

bonates  and  arseniates  of  copper  but  lower  down  the 
ore  is  variegated.  The  veins  are  unproductive  in  the 
slate.  At  Roraas,  there  are  no  veins,  the  ore  being 
disseminated  in  chlorite  slate,  forming  "  fahlbands." 

The  deposits  in  Sweden  occur  chiefly  in  quartzose, 
micaceous  and  calcareous  beds,  contained  usually  in 
gneiss.  Dalecarlia  is  the  principal  mining  region.  The 
mines  of  Garpenberg,  in  that  province,  have  been  worked 
since  the  twelfth  century  and  are  now  1000  feet  deep.  At 
Areskuttan,  the  ores  are  pyritous,  and  diffused  through 
crystalline  schists,  forming  fahlbands.  At  Gustavsberg, 
the  fahlband  averages  thirteen  to  sixteen  feet  in  thickness 
and  often  exceeds  that.  The  ore  yields  only  from  three 
to  four  per  cent,  of  copper. 

Falun  is  a  famous  mining  region,  now  nearly  exhausted. 
The  ore  is  poor,  containing,  after  picking  by  hand,  only 
3J  to  4  per  cent,  of  copper.  The  rock  in  which  it  is 
contained,  is  a  gray  quartzose  mass,  containing  little 
plates  of  mica.  It  is  divided  into  irregular  ovoid  masses, 
by  curved  or  undulated  bands  of  chlorite,  called 
"  skolar."  Along  these  are  found  the  principal  con- 
centrations of  the  ore.  The  Storgrufva,  or  great  mine, 
has  been  worked  for  centuries  upon  the  larger  of  these 
masses,  which  is  now  found  to  be  a  huge  inverted  cone, 
with  a  rounded  apex.  The  surface  dimensions  of  the 
mass,  are  800  by  500  feet.  The  interior  is  chiefly  iron 
pyrites,  the  copper  ore  lying  outside  and  forming  a  kind  of 
envelope  for  it.  The  depth  of  the  workings  is  about  1,100 
feet. 

The  entire  produce  of  Sweden  in  1850  was  a  little 
over  1,400  tons,  that  of  Norway,  for  five  years  before, 
averaged  annually  567  tons. 


MINES  OF  COPPER.  207 

AFRICAN  MINES. 

Algiers.  Near  the  foot  of  the  Moazaia  Pass,  a  cop- 
per mine  has  been  worked  for  some  time.  The  veins 
consist  of  spathic  iron  and  grey  copper  ore,  and  are 
found  in  strata  belonging  partly  to  the  gault  and 
partly  to  the  middle  tertiary. 

ASIATIC  MINES. 

India.  Copper  is  found  in  the  Ramghur  Hills,  about 
150  miles  from  Calcutta.  The  ore  is  said  to  be  abun- 
dant, but  the  mines  are  badly  worked.  The  natives 
smelt  the  ore  with  charcoal. 

Japan. — The  copper  from  this  secluded  empire  has 
long  been  celebrated  for  its  purity.  About  a  thousand 
tons  are  annually  exported,  chiefly  to  China  and  Hol- 
land. But  little  is  known  concerning  the  mode  in  which 
it  occurs.  From  what  Ksempfer  says,  much  of  it  would 
appear  to  be  native.  We  quote  his  words. 

"It  is  at  present  dug  up  chiefly  in  the  provinces  of 
Suruga,  Atsingo  and  Kijnokuni.  That  of  Kijnokuni  is 
the  finest,  most  malleable  and  fittest  for  work  of  any  in 
the  world.  That  of  Atsingo  is  coarse,  and  seventy  cat- 
tis  of  it  must  be  mixed  with  thirty  cattis  of  the  Kijnese 
to  make  it  malleable  and  fit  for  use.  That  of  Suruga  is 
not  only  fine  and  without  faults,  but  charged  with  a  con- 
siderable quantity  of  gold,  which  the  Japanese  at  pre- 
sent separate  and  refine  much  better  than  they  did  for- 
merly, which  occasions  great  complaints  among  the 
refiners  and  Brahmins  on  the  coasts  of  Coromandel.  All 
the  copper  is  brought  to  Saccai,  one  of  the  five  imperial 
towns,  where  it  is  refined  and  cast  into  small  cylinders, 


208  MINES  OF  COPPER. 

about  a  span  and  a  half  long  and  a  finger  thick,  As 
many  of  these  cylinders  as  amount  to  one  pickel,  or 
125  pounds  in  weight,  are  packed  up  into  square  wooden 
boxes  and  sold  to  the  Dutch.  There  is  besides  a  sort  of 
coarse  copper,  which  is  cast  into  large,  flat,  roundish 
lumps  or  cakes,  and  is  bought  a  great  deal  cheaper  than 
the  other,  as  it  is  also  much  inferior  in  goodness  and 
beauty." 

AUSTRALIAN   MINES. 

Several  mines  have  been  worked  in  this  great  island, 
in  a  district  not  very  far  distant  from  Adelaide.  The 
most  celebrated  of  these  is  the  Burra-Burra  mine. 

The  vein  occurs  in  a  rock  corresponding  with  the  kil- 
las  of  Cornwall,  and  contains  the  green  carbonate  and 
the  red  oxide  of  copper.  So  productive  is  the  mine, 
that,  notwithstanding  its  distance  from  Adelaide,  (eighty 
six  miles,)  the  badness  of  the  road,  the  want  of  wood 
for  timbering  the  mine  and  smelting  the  ore,  very  large 
profits  have  been  made.  The  mine  was  opened  in  Sep- 
tember, 1845.  Up  to  January,  1850,  only  <£6  had  been 
paid  in  on  each  share,  yet  the  stock  was  quoted  at  <£157. 
In  March,  1853,  a  dividend  of  £5  per  share  on  2464 
shares,  was  paid.  The  whole  amount  of  dividends  paid 
from  the  opening  of  the  mine  to  that  date  was  X135  per 
share.  In  August,  1851,  the  discovery  of  gold  was 
made  and  the  miners  were  all  attracted  to  the  deposits 
of  the  more  valuable  metal.  The  produce  of  the  six 
months,  ending  on  September  30th  of  that  year,  was 
10,732  tons  of  ore,  in  which  the  profits  were  ,£49,506. 
The  directors  refused  to  declare  more  dividends  till  more 


MINES  OF  COPPER.  209 

workmen  could  be  obtained.  Since  then  the  payment 
of  dividends  has  been  resumed.  The  last  paid  was  on 
June  4th,  1856,  amounting  to  <£5  per  share.  Up  to 
that  time  the  whole  sum  paid  in  dividends  was  =£170. 

Kapunda  mine  is  next  to  Burra-Burra  in  richness. 
It  shipped  to  England  in  1846  and  1847,  2768  tons  of 
ore,  yielding  from  20  to  50  per  cent,  of  copper. 

The  entire  amount  of  metallic  copper  furnished  by 
the  Australian  mines  between  the  years  1844  and  1853  is 
stated  by  Whitney  to  have  been  19,620  tons.  The 
gold  excitement  having  caused  a  great  falling  off  in  the 
produce  of  copper,  the  mines  have  not  yet  fully  recovered. 

SOUTH   AMERICAN   MINES. 

Peru. — The  copper  ores  of  this  country  occur  in  two 
distinct  formations,  in  the  granitic  and  igneous,  and  in 
stratified  rocks.  In  the  former,  whatever  the  nature  of 
the  ores,  they  never  contain  silver.  The  latter,  besides 
regular  silver  ores  and  beds  of  argentiferous  galena,  also 
carry  silver  in  the  copper  ores. 

Near  Antarangra  a  vein  is  worked  which  furnishes 
rich  ores.  These  are  smelted  and  yield  a  regulus,  con- 
taining 50  per  cent,  of  pure  copper,  which  is  sent  to 
England  to  be  worked.  Near  Colcabamba  is  another 
furnace,  smelting  ores  which  occur  in  a  segregated  mass 
in  the  granite.  There  are  numerous  veins  of  argentifer- 
ous copper  ores  in  the  districts  of  Ninobamba  and  Cas- 
tra  Virequa,  which  were  formerly  wrought  very  exten- 
sively by  the  Spaniards.  Recently  several  companies 
have  been  formed  in  Peru  to  resume  the  workings.  The 
amount  of  copper  furnished  by  Peru  is  not  exactly 
18* 


210  MINES  OF  COPPER. 

known.     Mining,  like  every  other  pursuit,  is  much  re- 
tarded by  the  political  commotions  of  the  country. 

Chili. — Domeyko  divides  this  country  into  two  ranges 
of  mountains,  the  Andes,  and  the  Cordilleras  of  the 
coast,  which  are  made  up  of  three  formations  belonging 
to  different  geological  epochs.  The  coast  range  consists 
of  granitic  or  porphyritic  masses  running  into  diorite  and 
greenstone.  The  rock  found  most  frequently  in  the 
neighbourhood  of  metallic  veins  is  a  green  porphyry  in 
white  felspar.  This  formation  occupies  the  entire  Paci- 
fic coast  and  extends  as  far  in  the  interior  as  the  east- 
ern slope  of  the  Cordilleras  of  the  coast.  Here  begins 
a  secondary  stratified  formation  of  an  epoch  anterior  to 
the  upheaval  of  the  Andes.  This  rests  upon  the  first 
named  formation,  which  makes  its  appearance  beyond 
them  on  many  points  of  the  loftiest  ridge  of  which  it 
often  forms  a  portion  of  the  highest  peaks.  The  first 
named  formation  is  barren,  but  this  contains  numerous 
metalliferous  veins.  It  appears  to  belong  to  the  Juras- 
sic or  cretaceous  system.  In  the  north,  it  contains  cal- 
careous and  compact  fossiliferous  rocks,  but  to  the  south 
these  entirely  disappear.  Throughout  they  are  subor- 
dinate to  the  stratified  porphyry  and  compact  schistose 
or  brecceoidal  rocks  that  form  the  bulk  of  the  chain  of 
the  Andes.  This  secondary  formation  varies  in  its  dis- 
tance from  the  coast  and  in  its  elevation.  In  the  pro- 
vince of  Atacama,  it  is  twenty  or  twenty-five  miles  from 
the  sea  and  has  an  elevation  of  1500  feet ;  in  the  south- 
ern provinces  it  is  not  found  within  twice  that  distance, 
nor  until  a  great  altitude  is  attained,  sometimes  near 
the  summits  of  the  Andes.  The  tertiary  beds,  which 


MINES  OF  COPPER.  211 

have  been  deposited  since  the  uplift,  rest  upon  this 
secondary  formation. 

The  gold  veins  are  found  in  the  old  granite  masses  ; 
the  copper  devoid  of  silver,  antimony  or  arsenic,  among 
the  diorites,  porphyries,  sienites  and  other  eruptive  rocks 
in  the  vicinity  of  the  secondary  formation.  The  chlo- 
rides and  native  amalgams  of  silver  are  found  near  the 
line  of  contact  of  the  primary  and  secondary  forma- 
tions ;  arseniates  and  sulpho-arseniates  of  copper  and 
silver  farther  east,  and  argentiferous  sulphurets  of  cop- 
per, sulphuret  of  lead,  argentiferous  blende  and  pyrites 
still  nearer  the  Andes. 

The  district  to  the  north  of  the  valley  of  Huasco  is 
very  rich,  especially  in  silver.  In  1842,  there  were  one 
hundred  mines  of  silver,  four  of  gold,  and  forty  of  cop- 
per in  operation  in  the  department  of  Copiapo  alone.  In 
1850,  the  silver  mines  had  increased  to  two  hundred  and 
ninety,  the  gold  to  six,  while  those  of  copper  had  dimi- 
nished to  thirty. 

The  mines  in  the  vicinity  of  Copiapo  were  originally 
worked  for  gold,  which  was  produced  in  great  abundance 
by  the  upper  part  of  the  vein.  When  that  metal  began 
to  fall  off,  copper  took  its  place.  In  1845,  there  were 
fifty  mines  at  work,  producing  twenty-five  per  cent,  ore, 
most  of  which  was  sent  to  England,  though  a  portion 
was  smelted  on  the  spot.  The  principal  vein  at  Cerro 
Blanco  was  worked  for  silver,  the  chloride  of  which  was 
found  in  the  upper  part  of  the  vein.  At  a  depth  of  two 
hundred  feet,  both  this  and  native  silver  had  disap- 
peared, and  gray  copper,  rich  in  silver,  took  its  place. 
Lower  down  it  passed  into  gray  copper  and  galena,  and 


212  MINES  OF  COPPER. 

before  the  miners  had  reached  the  depth  of  six  hundred 
feet,  copper  and  iron  pyrites  constituted  the  entire  con- 
tents of  the  vein.  It  was  then  abandoned  by  the  origi- 
nal holder,  and  finally  sold  to  an  Englishman,  who 
erected  furnaces  on  the  spot,  smelted  the  ores  which 
contained  from  twenty-five  to  thirty  per  cent,  of  copper, 
and  sent  the  produce  through  Huasco. 

South  of  the  valley  of  Huasco,  and  nearest  the  coast, 
the  most  important  mines  are  those  of  San  Juan  and 
Higuera.  They  occur  in  diorite,  and  furnish  oxide  of 
copper  and  copper  pyrites.  In  1845,  their  product  ex- 
ported was  over  5,800  tons,  besides  what  was  smelted 
in  Peru.  Lieutenant  Gillies  reports  their  production  in 
1851  to  be  4,500  tons.  At  Los  Camerones,  a  vein  en- 
closed between  dioritic  rocks  composed  of  white  feldspar 
and  black  amphibole,  crops  out  on  the  southern  face  for 
nearly  half  a  mile.  The  surface  ores  are  carbonates, 
silicates  and  oxides  ;  the  deeper,  copper  pyrites  and  eru- 
bescite.  The  gangues  of  the  oxides  are  argillaceous 
and  ferruginous,  containing  micaceous  iron ;  while  those 
of  the  sulphurets  are  quartzose,  containing  much  tremo- 
lite.  This  is  an  old  mine,  and  at  one  time  produced 
ores  of  fifty  per  cent.  At  present,  it  is  worked  by  an 
English  company,  who  take  out  1200  tons  a  year, 
averaging  from  fifteen  to  twenty  per  cent.  Those  which 
yield  more  than  twenty-four  per  cent,  are  shipped  to 
England;  those  of  seven  and  eight  per  cent,  are  rejected, 
and  the  rest  are  smelted  on  the  spot  in  reverberatory 
furnaces,  the  fuel  used  in  which  consists  of  arborescent 
cacti  and  branches  of  shrubs.  The  department  of  Co- 
quimbo  is  also  abundantly  supplied  with  copper  ores. 


MINES  OF  COPPER.  213 

A  large  amount  of  this  copper  is  smelted  on  the  coast 
and  sent  off  either  as  regulus  or  as  pig  copper,  though 
some  of  it  is  worked  up  into  sheathing  and  sold  at 
Valparaiso. 

Argentine  Republic.  Some  valuable  ores  of  copper 
have  been  discovered  in  the  Maldonado  mountains.  They 
are  native  copper,  red  oxide  of  copper,  and  erubescite. 

MINES   OF   THE   WEST   INDIA   ISLANDS. 

Jamaica.  Several  English  companies  are  now  engaged 
in  working  the  mines  of  this  island,  some  of  which  pro- 
mise very  well.  The  stratified  rocks  of  this  island  belong 
to  the  Silurian  age,  but  there  are  large  areas  of  por- 
phyry, granite,  trap,  greenstone,  gneiss  and  chlorite 
slate. 

The  mines  are  not  yet  fully  developed,  and  our  infor- 
mation concerning  them  is  scanty.  The  Clarendon 
Consols,  in  Clarendon  Parish,  has  a  large  lode,  fre- 
quently disturbed,  composed  of  porphyry  and  siliceous 
matter  with  spots  of  yellow  ore.  It  is  hard,  and  as  yet 
has  been  very  little  worked.  The  capital  is  .£80,000. 
Wheal  Jamaica,  or  Charing  Cross  Mine,  in  the  same 
parish,  is  in  the  south-east  flank  of  the  same  mountain 
which  contains  the  last-named  mine.  The  lode  is  four 
or  five  feet  wide,  underlying  from  ten  to  twelve  inches 
in  the  fathom.  The  mountain,  rising  to  a  height  of 
eight  hundred  feet  above  the  valley,  affords  a  good 
opportunity  for  cutting  adits,  which  have  been  driven  at 
distances  of  twelve  or  thirteen  fathoms  apart.  The 
upper  levels  are  ferruginous,  but  free  from  gossan  at  a 
moderate  depth  below  the  surface.  The  veinstone  is 


214  MINES  OF  COPPER. 

quartyose,  carrying,  in  the  fifty-eight  fathom  level,  yel- 
low pyrites  and  a  little  gray  ore,  mixed  with  carbonates 
and  silicates.  The  ore  is  found  in  branches,  some  of 
which  are  a  foot  in  width.  The  surrounding  rocks  are 
porphryites.  The  nominal  capital  is  ,£100,000;  though 
there  had  been  issued,  up  to  the  date  of  the  last  report 
which  we  have  seen,  but  35,000  shares  of  <£!  each,  on 
25,000  of  which  12s.  had  been  paid  in. 

On  the  west  side  of  the  Liguanian  mountains,  a  range 
of  limestone  hills  two  thousand  or  three  thousand  feet 
high,  at  Mt.  Salust,  there  are  seams  of  crystalline  garnet 
rock  carrying  yellow  copper.  Simpson  s  lode,  five  feet 
wide,  is  composed  of  granite  carrying  yellow  ore. 

Cuba.  Formerly  the  mines  on  this  island  were  con- 
sidered very  valuable,  and  did  actually  produce  large 
quantities  of  excellent  ore.  A  few  years  ago,  they  fell 
off  their  yield,  but  seem  to  be  at  present  rising  again  in 
importance.  The  ores  are  not  believed  to  be  in  regular 
veins,  but  in  beds  and  masses,  subordinate  to  igneous 
rocks,  especially  greenstone  and  serpentine.  The  gangues 
are  chiefly  quartz,  but  sometimes  limestone.  The  prin- 
cipal ore  is  the  yellow  sulphuret  or  copper  pyrites, 
which  is  occasionally  mixed  with  hydrated  oxide  of  iron ; 
while  near  the  surface,  are  found  carbonates,  oxides  and 
silicates.  Some  very  remarkable  ores  have  been  sent 
in  from  this  island.  From  the  neighborhood  of  St.  Jago 
we  have  received  a  black  ore,  in  great  masses,  averaging 
about  ten  per  cent.,  containing  scarcely  any  gangue, 
but  composed  almost  entirely  of  iron  pyrites  and  covel- 
line,  or  indigo-copper.  A  yellow  copper  sand,  as  light 
as  flour,  but  containing  thirty  per  cent,  of  copper,  has 
also  been  sent  in. 


MINES  OF  COPPER.  215 

There  are  two  principal  companies,  both  English,  now 
at  work  on  the  island.  The  Cope  mines,  or  the  consoli- 
dated mines  of  the  Cope  association,  are  the  most 
important.  They  have  been  successfully  worked  since 
1834.  Their  product  has  fluctuated  considerably  since 

1836,  the  highest  annual  yield  being  22,741  tons,  and 
the  lowest  2,077.     The  average  for  ten  years,  ending  in 
1849,  was  nearly  19,000  tons.     For  the  quarter  ending 
September  30th,  1856,  this  company  sold  in  Swansea, 
3,529  tons  of  ore  for  £52,325  11s.,  while  all  the  other 
sales  of  Cuba  ore  amounted  to  467  tons  at  .£26,092  11s. 

The  Royal  Santiago  Mining  Company  was  formed  in 

1837,  and  has  17,000  shares,  on  each  of  which  £13  was 
paid  in.     From  1840  to  1845,  55,540  tons  of  ore  were 
raised,  at  a  cost  of  £247,043,  or  about  $22  per  ton. 
They  brought  $557,533,  thus  yielding  a  clear  profit  of 
£48  per  ton.     Up  to  1848,  £33  4s.  had  been  paid  in 
dividends,  but  since  then,  the  mine  has  been  worked 
at  a  loss.      In  1853,  an  assessment  was  levied  on  the 
shares. 

COPPER  MINES  IN  THE  UNITED  STATES. 

In  describing  the  valuable  deposits  of  this  mineral 
which  occur  in  this  country ;  the  arrangement  of  Whit- 
ney will  be  adopted.  He  describes  the  American  mines 
under  three  heads,  I.  the  Lake  Superior  Region,  II. 
Copper  deposits  of  the  Mississippi  Valley,  and  III.  Cu- 
priferous deposits  of  the  Atlantic  States.  The  latter  he 
divides  into  three  groups. 

1.  "  Copper-bearing  veins  of  the  Appalachian  chain,  in 
rocks  of  the  metamorphic  palaeozoic  age ;  ores  chiefly 


216  MINES  OF  COPPER. 

pyritons  ;  deposits  mostly  in  the  form  of  segregated 
veins ;  localities  numerous  extending  along  the  flanks  of 
the  great  Appalachian  chain,  from  Vermont  to  Tennes- 
see worked  in  numerous  places. 

"  2.  Deposits  in  the  sandstones  and  associated  trap- 
pean  rocks,  of  the  formation  commonly  called  the  New 
Red  Sandstone  ;  ores,  carbonate,  oxide  and  native  cop- 
per, principally ;  contact  deposits,  usually  of  limited 
depth.  Localities  numerous  in  Connecticut  and  New 
Jersey;  formerly  extensively  worked,  but  now  abandoned. 

"  3.  Veins  traversing  the  new  red  sandsone  and  older 
metamorphic  rocks,  and  bearing  principally  ores  of 
copper  in  the  sandstone.  Locality  confined  to  Montgo- 
mery and  Chester  Counties,  Pennsylvania,  and  these 
extensively  worked." 

COPPER  REGION  OF  LAKE  SUPERIOR. 

Attention  was  very  early  called  to  the  remarkable 
deposits  of  native  copper  upon  the  shores  of  this  great 
lake.  The  first  mention  of  it  appears  to  have  been  in 
the  Missionary  Reports  of  the  Society  of  Jesus,  for 
1659-60.  It  is  next  spoken  of  by  Claude  Allouez,  a 
Jesuit  missionary,  who  visited  this  region  in  1666.  He 
speaks  of  having  seen  pieces  of  copper  of  ten  or  twenty 
pounds  weight,  which  the  savages  reverenced  as  house- 
hold gods,  and  of  having  passed  the  site  of  a  great  rock 
of  copper,  then  buried  in  sand.  In  the  Reports  for 
1669-70,  Father  Dablon  reports  a  marvelous  story,* 

*  They  said  that  a  party  visited  the  Island,  and  in  cooking  their 
meals,  observed  that  the  stoves  they  used  to  heat  the  water  were 
nearly  all  copper.  They  took  plates  of  copper  with  them,  and  as  they 


MINES  OF  COPPER.  217 

which  was  told  him  by  the  Indians,  concerning  a  copper 
island  about  fifty  leagues  from  the  Saut,  which  he  inter- 
prets as  a  cause  of  poisoning  from  the  metal,  loose 
pieces  of  which  the  savages  used  in  cooking  their  meat. 
Charlevoix,  whose  travels  were  published  in  1744,  cor- 
roborates these  accounts,  and  mentions  the  fact  that  a 
brother  of  the  order  made  chandeliers,  crosses  and 
censers  of  the  copper  which  was  there  found. 

About  1763,  a  practical  Englishman,  Alexander  Henry, 
passed  through  this  region.  He  narrowly  escaped  being 
massacred  by  the  Indians,  but  in  spite  of  his  trouble 
he  kept  his  eyes  open  to  his  own  interest.  In  1771,  he 
commenced  mining  operations  in  the  clay  bluffs,  near 
the  forks  of  the  Ontonagon  river.  The  following  year 
he  transferred  his  workmen  to  the  vein  on  the  north 
shore,  but  being  discouraged  by  the  contraction  of  the 
lode  from  four  feet  to  four  inches,  he  became  disgusted 
and  finally  abandoned  his  workings. 

In  1819,  General  Cass  and  Mr.  H.  R.  Schoolcraft 
passed  through  this  region  and  visited  the  famous  mass 
of  native  copper  on  the  Ontonagon.  In  1823,  Major 
Long  and  his  party  saw  the  scattered  boulders  of  this 
formation.  Nothing,  however,  came  of  all  these  obser-< 
vations,  the  general  impression  being  that  the  wildness 
of  the  country  and  its  distance  from  setlements  ren- 
dered these  enormous  natural  resources  valueless,  at 
at  least  for  many  years. 

were  pushing  off  from  the  shore,  they  heard  a  voice  exclaiming,  "  Who 
are  the  thieves  that  carry  off  the  cradles  and  toys  of  my  children  ?" 
The  whole  party  died,  one  shortly  after  reaching  home,  the  others  on 
their  voyage. 

19 


218  MINES  OF  COPPER. 

The  first  impulse  to  mining  in  this  district  was  given 
by  Dr.  Douglass  Houghton,  state  geologist  of  Michigan, 
who,  in  1841,  in  his  annual  report  to  the  Legislature, 
gave  an  account  of  the  geology  of  the  country,  and  the 
first  scientific  description  of  the  copper  deposits.  Sub- 
sequently, he  devised  an  admirable  plan  for  developing 
the  resources  of  this  region,  and  had  commenced  carry- 
ing it  into  practice  when  his  sudden  death  by  drowning 
put  a  stop  to  these  important  observations. 

In  1843  was  ratified  with  the  Chippewas  a  treaty, 
which  put  the  United  States  in  possession  of  the  terri- 
tory as  far  west  as  the  Montreal  river  and  southerly  to 
the  boundary  of  Wisconsin.  The  same  year  numbers  of 
persons  entered  land  in  this  neighborhood,  by  the  provi- 
sions of  a  joint  resolution  of  Congress  in  reference  to 
the  "lead  lands"  of  Illinois,  passed  as  far  back  as  1818. 
At  first  the  applicant  was  allowed  to  select  a  tract  three 
miles  square,  but  afterwards  he  was  limited  to  one  mile 
square.  He  was  required  to  make  selection  within  a 
year,  to  mark  the  corners,  to  leave  a  person  in  charge 
to  point  out  the  bounds  and  to  transmit  to  the  proper 
department  a  description  and  plat  of  the  same.  On  the 
^receipt  of  this  plat,  the  applicant  was  entitled  to  a  lease 
of  three  years,  renewable  for  three  additional  years,  on 
condition  that  he  should  work  the  mines  with  due  dili- 
gence and  skill,  and  pay  the  federal  government  six  per 
cent,  of  all  the  ores  raised. 

As  a  natural  consequence  of  these  liberal  provisions, 
a  great  influx  of  speculators  and  their  agents  took  place 
into  this  territory.  The  first  mining  operations  were 
commenced  in  1844.  Masses  of  native  copper 


MINES  OF  COPPER.  219 

containing  silver  were  found,  and  numerous  veins  were 
discovered.  About  a  thousand  permits  were  granted  by 
the  department,  and  nine  hundred  and  sixty-one  sites 
selected.  Sixty  leases  for  tracts  three  miles  square, 
and  one  hundred  and  seventeen  for  tracts  one  mile 
square,  were  granted,  and  mining  companies  were  or- 
ganized under  them.  "  Most  of  the  tracts  covered  by 
these  were  taken  at  random,  and  without  any  explora- 
tions whatever ;  indeed,  a  large  portion  of  them  were  on 
rocks  which  do  not  contain  any  metalliferous  veins  at 
all,  or  in  which  the  veins,  when  they  do  occur,  are  not 
found  to  be  productive."  The  excitement  reached  its 
height  in  1846.  Quantities  of  stock  were  sold  which' 
represented  no  value  whatever,  and  this  reckless  specu- 
lation injured  the  reputation  of  the  mines. 

In  184T,  the  country  was  almost  deserted,  only  about 
half  a  dozen  companies,  out  of  all  that  had  been  formed, 
being  engaged  in  mining. 

In  1846,  further  grants  of  land  were  suspended  as 
illegal,  the  resolution  in  regard  to  lead  not  covering 
"  copper  lands,  and  the  following  year  congress  passed  an 
act  authorizing  the  sale  of  the  lands  and  a  geological 
survey.  For  the  latter  purpose,  Dr.  Charles  T.  Jack- 
son was  appointed,  but  after  having  spent  two  seasons 
in  these  explorations,  he  resigned,  whereupon  the  work 
was  confided  to  Messrs.  Foster  &  Whitney,  who  have 
given  a  very  full  and  satisfactory  account  of  the  geology 
of  the  country  and  its  prospects  as  a  mining  region. 
Meanwhile,  the  actual  miners  had  made  considerable 
progress  in  their  excavations,  and  as  they  purchased 
lands  after  thorough  examination,  confidence  was  gradu- 


220  MINES  OF  COPPER. 

ally  restored.  By  the  time  the  United  States  Survey 
had  been  completed  and  its  results  published,  in  1850, 
copper  mining  had  become  an  established  business. 

The  report  of  Foster  &  Whitney  contains  some  very  in- 
teresting details  of  the  discovery  of  ancient  excavations 
for  mining  purposes.  Some  of  these  are  quite  extensive, 
reaching  the  depth  of  fifty  feet,  and  containing  rude 
implements  for  boiling  water,  stone  hammers,  copper 
gads  and  other  mining  tools.  It  would  appear,  from 
some  of  the  indications,  that  fire  was  the  agent  used  to 
disintegrate  the  rock.  Some  idea  of  the  extent  of  their 
operations  may  be  formed  from  the  fact  that  one  of  the 
•  explorers  found  a  mass  of  native  copper,  weighing  six 
tons,  which  had  been  detached  by  these  ancient  miners 
and  supported  on  billets  of  oak,  preparatory  to  removal. 
The  age  of  these  works  may  be  inferred  from  that  of  a 
pine-tree  stump  growing  out  of  one  of  the  mounds  of 
rubbish  from  the  mine.  This  contained  three  hundred 
and  ninty-five  annual  rings,  so  that  the  exploration  must 
have  been  made  before  Columbus  started  from  Europe 
on  his  memorable  voyage  of  discovery. 

A  rapid  survey  of  the  geology  of  this  region  forms  a 
necessary  prelude  to  any  remarks  upon  its  metalliferous 
veins.  In  this  we  follow  Mr.  Whitney. 

Lake  Superior  lies  in  a  basin  of  sandstone,  belonging 
to  the  lower  Silurian  system,  and  believed  to  be  the 
equivalent  of  the  Potsdam  sandstone,  hitherto  supposed 
to  be  the  lowest  fossiliferous  rock  in  this  country.  The 
strata,  on  both  sides,  dip  towards  the  centre  of  the  lake. 
Going  southward  from  any  point  between  Saut  Ste. 
Marie  and  the  Pictured  Rocks,  the  traveller  passes  over 


MINES  OF  COPPER.  221 

the  upper  members  of  the  Silurian  system,  successively 
cropping  out  above  the  sandstone,  with  a  slight  southerly 
dip.  Here  the  sandstone  rock  lies  nearly  horizontally, 
is  coarse-grained,  and  but  little  coherent.  Its  whole 
thickness  does  not  appear  to  exceed  300  or  400  feet. 
Where  it  comes  in  contact  with  the  older  azoic  rocks,  at 
about  the  Carp  and  Chocolate  rivers,  it  rests  unconform- 
ably  upon  them,  being  deposited  nearly  horizontally  on 
their  upturned  edges.  At  Keweenaw  Point,  a  peninsula 
extending  from  the  southern  shore,  in  a  northeasterly 
direction  for  nearly  seventy  miles,  the  character  of  the 
rock  changes.  It  becomes  thicker,  is  tilted  at  a  consid- 
erable angle,  and  is  associated  with  great  beds  of  con- 
glomerate and  trappean  rock. 

If  this  line  of  upheaval  of  trap  be  traced,  it  will  be 
found  to  consist  of  a  series  of  parallel  ridges,  usually 
two  in  number,  but  sometimes  three  or  more,  extending 
in  a  southwesterly  direction  along  the  whole  line  of  the 
lake,  at  a  distance  of  a  few  miles  from  it,  gradually 
diminishing  in  elevation  as  they  traverse  Wisconsin,  and 
disappearing  before  they  reach  the  Mississippi.  Their 
average  height  above  the  lake  is  500  feet.  Towards 
the  south  they  present  steep  mural  faces,  while  they  dip 
at  a  moderate  angle  towards  the  north.  This  line,  com- 
monly known  as  the  "Trap  Range,"  for  120  miles  in 
length  and  26  in  width,  is  metalliferous,  along  it  occur 
the  copper  mines  of  the  southern  shore  of  Lake  Supe- 
rior. 

The  rocks  of  this  range  are  various  in  character,  but 
most  of  them  are  manifestly  igneous,  and  are  supposed 
to  have  been  poured  out  at  the  same  time  that  the  depo- 
19* 


222  MINES  OF  COPPER. 

sition  of  the  sandstone  was  going  on.  In  the  more  ele- 
vated and  central  portion  of  the  range,  igneous  rocks 
predominate,  containing  intercalated  beds  of  conglomer- 
ate, of  very  inconsiderable  thickness,  between  heavy 
masses  of  trappean  rock.  Upon  the  sides,  the  trap 
gradually  thins  out,  while  the  conglomerate  thickens,  till 
in  its  turn  it  gives  way  to  the  sandstone.  This  system 
of  bedded  trap  and  interstitial  conglomerate  is  very 
extensive,  some  of  its  beds  acquiring  a  thickness  of  seve- 
ral thousand  feet. 

The  usual  mineral  constituents  of  the  trap  are  labra- 
dorite  and  augite,  with  a  smaller  proportion  of  other 
minerals,  among  which  the  most  abundant  are  magnetic 
oxyd  of  iron,  chlorite  and  epidote.  The  felspathic  and 
augitic  portions  form  a  homogeneous  paste,  in  which 
the  other  minerals  are  embedded,  the  difference  in  these 
rocks  arising  rather  from  their  mechanical  structure  than 
their  chemical  composition.  Thus  on  Keweenaw  Point, 
there  are-  two  well-marked  varieties  of  trap,  between 
which  are  innumerable  others  partaking  more  or  less  of 
one  or  the  other  character.  One  of  these  is  porous  or 
vesicular  in  structure,  containing  cavities  of  various 
sizes,  which  have  since  the  formation  of  the  rock,  been 
filled  with  other  minerals.  The  other  is  very  compact 
and  finely  crystalline.  In  the  former  or  amygdaloidal 
variety,  provided  it  be  not  too  soft  or  porous,  is  found 
the  largest  amount  of  copper,  the  compact  variety  being 
unproductive. 

The  remarkable  peculiarity  of  this  region  is  the  enor- 
mous quantity  of  native  copper  which  is  found  in  its 
veins.  Elsewhere,  native  copper  has  been  regarded  as 


MINES  OF  COPPER.  223 

rather  an  accidental  accompaniment  of  other  ores,  but 
here  it  constitutes  the  entire  mass  of  the  metallic  con- 
tents, and  this  character  does  not  change  at  the  greatest 
depth  which  the  workings  have  attained.  Out  of  the 
bedded  trap,  however,  sulphurets  make  their  appearance. 
"  Thus  in  the  Bohemian  or  southern  range  of  the  Ke- 
weenaw  Point,  which  seems  to  have  been  protruded  at  a 
late  epoch,  and  under  different  conditions,  and  to  have 
tilted  up  the  system  of  bedded  trap  and  interstratified 
conglomerate  which  lies  to  the  north,  the  veins  bear 
only  sulphuret  of  copper  ;  and  on  the  north  shore,  where 
the  trappean  rocks  are  most  developed,  they  appear  to 
be  of  the  same  imbedded  character,  and  they  are  tra- 
versed by  powerful  veins  bearing  the  sulphurets  of  cop- 
per, zinc  and  lead." 

The  mines  of  Lake  Superior  are  divided  by  Mr.  Whit- 
ney into  four  groups:  1.  Keweenaw  Point;  2.  Isle  Roy- 
ale;  3.  Ontonagon;  4.  Portage  Lake. 

Keweenaw  Point  contains  a  large  number  of  mines, 
its  mining  region  extending  over  a  space  about  thirty- 
six  miles  long  by  two  or  three  broad.  From  its  eastern 
extremity  a  belt  of  metalliferous  trap  extends  through 
it,  in  a  nearly  east  and  west  direction,  gradually  curv- 
ing in  its  western  prolongation  towards  the  south.  There 
are  two  distinct  ranges,  the  Greenstone  and  the  South- 
ern or  Bohemian  Range.  The  former  comprises  a  line 
of  bluffs,  rising  sharply  from  the  valleys  of  Eagle  and 
the  Montreal  rivers,  which  drain  the  district,  rising 
near  its  centre,  and  flowing  through  it  longitudinally  in 
different  directions.  It  is  a  compact,  crystalline,  homo- 
geneous rock,  several  hundred  feet  thick,  dipping  to  the 


224  MINES  OF  COPPER. 

north  at  an  angle  of  twenty  or  thirty  degrees.  To  the 
south,  its  limits  are  well  defined.  It  rests  upon  a  stra- 
tum of  conglomerate,  accompanied  by  a  thin  layer  of 
consolidated  volcanic  ash,  and  below  this  lies  the  great 
southern  metalliferous  belt  of  Keweenaw  Point.  In 
this,  numerous  mines  have  been  opened,  which  always 
fail  in  metallic  contents  when  they  are  carried  into  the 
greenstone  above  the  conglomerate  and  trappean  ash. 

At  the  eastern  end  of  the  Point,  this  bed  of  conglom- 
erate is  thirty  or  forty  feet  thick,  but  it  gradually  thins 
out,  and  finally  disappears  near  the  Cliff  mine.  The 
main  features  of  the  distinction  between  the  greenstone 
and  the  amygdaloidal  trap,  however,  remain.  Between 
the  conglomerate  and  the  greenstone,  towards  the  west, 
are  occasionally  found  thin  seams  of  quartz,  which  often 
contains  sheets  and  particles  of  copper. 

To  the  south  of  this  thin  belt  of  conglomerate,  the 
amygdaloid  extends  for  two  or  three  miles ;  but  as  it 
lies  in  the  low  ground,  it  has  only  been  explored  by  un- 
derground workings,  which  have  not  as  yet  penetrated 
its  thickness,  nor  revealed  the  depth  of  the  beds  of  which 
it  is  composed. 

North  of  the  conglomerate,  the  greenstone  is  from  a 
quarter  of  a  mile  to  half  a  mile  wide,  and  gradually 
changes  to  amygdaloid  resembling  that  on  the  southern 
side  of  the  conglomerate.  This  "  northern  metalliferous 
amygdaloid  belt"  is  bounded  to  the  north  by  the  sand- 
stone, varies  in  width  from  a  mile  to  a  mile  and  a  half, 
and  contains  several  important  mines,  imbedded  in  a 
variety  of  trappean  layers.  Further  north  is  a  series 
of  alternating  belts  of  amygdaloid  and  sandstone  of 


MINES  OF  COPPER.  225 

moderate  thickness,  varying  from  50  to  500  feet;  and 
next  to  these  is  a  belt  of  conglomerate,  nearly  a  mile 
wide.  Beyond  is  another  bed  of  amygdaloid  rock,  about 
1500  feet  thick,  succeeded  by  conglomerate,  which  forms 
the  northern  portion  of  the  Point  from  its  extremity  as 
far  west  as  Agate  Harbor. 

The  mines  are  worked,  almost  exclusively,  in  metalli- 
ferous deposits  which  have  the  character  of  true  veins. 
They  cross  the  belts  of  rock  nearly  at  right  angles,  and 
have,  in  many  instances,  been  traced  through  all  the 
formations.  One  vein  is  known  to  have  been  worked  on 
both  sides  of  the  greenstone.  The  veins  change  charac- 
ter as  they  pass  through  the  different  belts.  In  the  con- 
glomerate their  gangues  are  calcareous,  the  copper  being 
usually  concentrated  into  large  masses.  In  one  instance, 
black  oxyd  of  copper  is  found  in  the  rock.  Mr.  Whit- 
ney thinks  it  probable  that  these  same  veins  extend 
across  the  valley  into  the  southern  range,  and  there  bear 
sulphurets. 

In  the  true  copper-bearing  rocks,  the  veins  are  made 
up  of  quartzose  rock,  mixed  with  calcareous  spar  and 
zeolitic  mineral,  of  which  prehnite  and  laumonite  are 
most  common.  The  most  favorable  vein-stone  contains 
crystallized  and  drusy  quartz  mixed  with  prehnite  and 
granular  carbonate  of  lime.  In  some  instances  the 
veins  are  brecciated,  i.  e.  made  up  of  fragments  of  the 
adjoining  rock,  cemented  by  the  usual  vein-stone.  At 
other  points  purely  calcareous  veins  have  been  worked 
in  the  trap,  but  they  are  now  regarded  as  worthless, 
especially  when  the  carbonate  of  lime  occurs  in  the  form 
of  coarsely  crystallized  spar.  Smaller  veins  or  strings 


226  MINES  OF  COPPER. 

are  made  up  almost  entirely  of  laumonite,  and  contain 
very  little  copper. 

"  The  width  of  the  productive  veins  is  usually  from 
one  to  three  feet;  they  sometimes  widen  out  to  ten  feet 
or  even  more,  but  rarely  continue  to  hold  those  dimen- 
sions for  any  considerable  distance.  The  wider  the  vein, 
as  a  general  rule,  the  richer  it  is  in  metallic  contents." 

But  one  system  of  veins  has  been  observed  in  this 
district.  They  are  remarkably  regular  in  their  course, 
which  is  nearly  at  right  angles  to  the  bearing  of  the 
formation.  They  are  sometimes  shifted  a  few  feet  to 
one  side  or  the  other,  as  they  pass  from  one  belt  to  an- 
other, but  there  are  no  regular  cross-fractures  or  coun- 
ter-lodes, such  as  prevail  in  most  extensive  metalliferous 
districts.  The  parallelism  of  the  productive  lodes  of 
Keweenaw  Point  is  very  remarkable.  They  have  no 
tendency  to  unite  together . 

The  dip  is  nearly  vertical,  the  underlay,  or  deviation 
from  the  perpendicular,  being  rarely  more  than  eight  or 
ten  degrees.  The  vein  is  usually  separated  from  the 
wall  rock  by  a  distinct  selvage  of  red  clay,  and  the  walls 
are  striated  or  polished.  The  copper  is  mixed  with  the 
vein-stone  in  pieces  varying  from  the  most  minute  specks 
and  strings  up  to  masses  of  one  to  two  hundred  tons 
weight.  In  accordance  with  the  size  of  the  pieces,  the 
copper  is  classed  under  three  varieties,  mass  copper, 
barrel-work  and  stamp-work. 

Masses  are  sometimes  met  with  twenty  or  thirty  feet 
in  length.  In  such  cases  the  rock  is  cleared  away  from 
one  side  of  the  mass,  and  it  is  detached  from  the  wall  by 
heavy  charges  of  powder  inserted  behind  it.  It  is  then 


MINES  OF  COPPER.  227 

cut  up  into  pieces  oi  convenient  size  for  lifting  through  the 
shaft.  This  is  a  very  tedious  and  costly  process,  several 
months  being  sometimes  occupied  in  dividing  and  remov- 
ing a  single  mass.  For  this  purpose  they  employ  chis- 
els having  a  cutting  edge  of  about  the  fourth  of  an  inch 
in  width,  and  varying  in  length  according  to  the  thick- 
ness of  the  mass  to  be  divided.  One  man  holds  and 
guides  the  chisel,  while  another  strikes  it  with  a  heavy 
sledge,  so  that  chips  are  gradually  taken  out  of  a  length 
equal  to  the  distance  to  be  cut  across,  and  a  thickness 
of  about  one-eighth  of  an  inch.  The  process  is  repeated 
till  the  mass  is  completely  severed.  The  expense  of 
this  operation  is  usually  about  six  dollars  for  every 
square  foot  of  surface  exposed  on  one  side  of  the  cut. 
On  reaching  the  surface,  further  subdivision  is  required, 
in  order  to  obtain  masses  convenient  for  shipment.  As 
thus  prepared,  the  vein-stone  not  being  entirely  removed, 
the  mass  copper  contains  70  or  80  per  cent,  of  pure 
metal,  though  sometimes,  being  almost  wholly  free  from 
foreign  matter,  it  yields  from  90  to  95  per  cent,  when 
smelted  in  the  furnaces.  This  test,  however,  cannot  be 
regarded  as  a  satisfactory  one  of  the  actual  amount  of 
metal  contained  in  these  masses,  since  some  of  the 
smelting  works  are  conducted  in  the  most  unscientific 
manner,  and  waste  an  enormous  quantity  of  copper. 

Barrel-work  includes  the  smaller  pieces,  weighing 
usually  a  few  pounds.  This  name  is  given  to  them  be- 
cause they  are  too  small  to  be  sent  away  without  being 
previously  packed  in  barrels.  Much  of  this  is  obtained 
during  the  preparation  of  the  stamp-work.  The  pieces 
are  well  hammered  to  free  them  from  adhering  vein- 


228  MINES  OF  COPPER. 

stone,  and,  as  thus  prepared,  contain  from  60  to  70  per 
cent,  of  pure  copper. 

Stamp-work  forms  a  large  portion  of  the  yield  of  all 
the  veins,  so  that  each  mine  requires  a  set  of  stamps 
containing  a  number  of  heads  proportioned  to  its  extent. 
The  rock  is  first  calcined  by  being  laid  upon  a  pile  of 
wood  which  is  then  kindled.  Care  is  taken  not  to  melt 
or  oxydize  the  copper.  The  rock  being  thus  rendered 
friable,  is  placed  under  the  stamps.  During  this  process 
of  preparation,  some  pieces  are  met  with  which  are  too 
large  to  be  put  under  the  stamps,  and  contain  too  much 
copper  to  allow  any  further  reduction  in  size.  These  are 
barreled  up,  and  the  rest  of  the  ore  is  placed  under  the 
stamps,  pounded,  washed  and  packed  up. 

A  full  account  of  the  mines  in  this  region,  beginning 
on  the  northern  metalliferous  belt,  is  given  by  Mr. 
Whitney,  from  whose  valuable  work  we  make  the  follow- 
ing abtract,  supplying  the  later  facts  from  recent  authen- 
tic documents  when  we  have  been  able  to  procure  them. 

The  New  York  and  Michigan  mine  was  opened  in 
1846,  and  continued  in  1847,  till  the  shaft  was  84  feet 
deep.  It  was  then  abandoned,  resumed  in  1852,  when 
the  shaft  was  continued.  In  September,  1853,  having 
reached  a  depth  of  150  feet,  it  was  finally  abandoned. 
A  drift  was  run  off  to  the  north  for  100  feet  or  or  more, 
and  the  vein  was  found  to  be,  in  some  places,  20  inches 
wide;  the  vein-stone  being  quartz  and  prehnite,  carry- 
ing a  little  copper.  Four  small  masses,  weighing  about 
1,800  Ibs.  were  shipped  in  1852.  This  mine,  being  sit- 
uated in  the  unproductive  green-stone,  could  not  be 
worked  with  profit. 


MINES  OF  COPPER.  229 

The  Clark  Mining  Company  commenced  operations 
in  the  autumn  of  1853,  on  a  vein  running  north  10° 
west,  a  foot  or  eighteen  inches  wide,  well  filled  with  cop- 
per. It  has  been  opened  at  several  points,  and  found 
to  be  well  defined  and  promising  favorably  for  success- 
ful working. 

The  Washington  Mining  Company  has  several  veins 
in  the  vicinity  of  Musquito  Lake,  but  had  not  yet  com- 
menced operations  at  the  date  of  Mr.  Whitney's  publi- 
cation. 

The  Agate  Harbor  Mining  Company  has  been  explor- 
ing, and  has  discovered  many  powerful  veins,  having  a 
course  of  about  south  19°  east. 

Adjoining  them  is  the  "Keliher  Vein,"  bearing  north 
25°  west,  being  from  two  to  eight  feet  wide,  having  a 
brecciated  vein-stone  containing  much  copper,  and 
opened  already  over  an  extent  of  2,500  feet. 

The  Eagle  Harbor  Mining  Company  has  explored 
this,  region  without  success. 

The  Native  Copper  Mining  Company  commenced 
operations  in  1852.  A  shaft  had  been  sunk  120  feet 
and  a  cross-cut  driven,  at  a  depth  of  ten  fathoms,  to  the 
vein.  The  vein  is  wide,  brecciated  and  unproductive. 

The  Copper  Falls  Mining  Company  was  originally 
formed  in  1845.  They  began  mining  in  1846  on  the 
"  Old  Copper  Falls  Vein."  The  workings  were  com- 
menced upon  a  belt  of  trap  only  170  feet  thick,  measured 
at  right  angles  to  the  dip,  arid  430  feet  across  on  the 
line  of  adit,  inclosed  between  two  beds  of  sandstone.  A 
shaft  was  sunk  53  feet  through  the  underlying  sandstone. 
In  the  trap,  the  vein  was  rich,  but  on  entering  the 
20 


230  MINES  OF  COPPER. 

sandstone,  it  rapidly  contracted  and  split  up  so  that  it 
was  not  thought  advisable  to  follow  it.  The  shaft  alluded 
to  was  therefore  sunk  and  cross-cuts  driven  in  each 
direction  for  forty  feet,  without  finding  the  vein.  The 
same  vein  has  been  traced  on  the  surface,  south  of  all 
the  belts  of  sandstone.  From  this  mine  $15,000  worth 
of  copper  was  taken,  while  on  it  $100,000  were  spent. 
This  resulted  entirely  from  a  want  of  proper  geological 
knowledge.  To  remedy  this  defect,  a  competent  geolo- 
gist was  employed,  who  surveyed  the  whole  region  and 
and  discovered  several  veins,  two  of  which,  the  Copper 
Falls  and  the  Hill  veins,  have  been  worked.  The  first 
was  opened  in  December,  1850,  and  the  second  a  year 
later. 

All  these  veins  are  nearly  parallel,  running  north  22° 
to  25°  west.  In  almost  every  instance  they  have  been 
traced  entirely  across  the  whole  belt  of  trap  north  of  the 
greenstone.  Upon  each  of  these  veins  some  shafts  have 
been  sunk,  and  large  quantities  of  copper  have  been 
taken  out.  According  to  the  report  of  the  superinten- 
dent, dated  March  1st  1854,  it  appears  that  they  yield 
865  pounds  to  the  fathom. 

The  Phoenix  Mining  Company  is  the  oldest  of  these 
organizations.  It  was  formed  in  1844,  under  the  title 
of  the  "Lake  Superior  Copper  Company."  By  direc- 
tion of  Dr.  C.  T.  Jackson,  work  was  commenced,  in  Oc- 
tober, 1844,  on  Eagle  river,  and  carried  on  through  the 
year  1845.  "  A  stamping  mill  and  crushing  wheels,  of 
a  kind  suitable  for  grinding  drugs,  were  erected  but 
soon  proved  to  be  entirely  unserviceable."  Up  to  March 
31,  1849,  about  $106,000  had  been  expended,  "about 


MINES  OF  COPPER.  231 

half  of  which  was  probably  for  actual  mining  work." 
The  principal  shaft  was  sunk  upon  a  "  pocket"  of  copper 
and  silver,  without  any  signs  of  a  regular  vein,  which 
soon  gave  out  entirely.  In  1846,  a  drift  was  run  off 
from  the  shaft  at  a  depth  of  ninety  feet,  towards  the 
river,  to  find  a  vein,  and  directly  under  the  river  the 
workmen  found  a  crevice,  filled  up  with  gravel.  This 
was  evidently  the  ancient  bed  of  the  Eagle  River. 
Workings  were  carried  on  and  a  large  pot-hole  was  found, 
filled  with  rounded  pieces  of  native  copper  and  silver. 
From  this  and  other  excavations,  18,000  pounds  of  cop- 
per were  taken,  as  well  as  much  silver,  most  of  which 
was  stolen  by  the  miners.  One  piece  of  silver,  weighing 
96.8  ounces  Troy,  came  in  possession  of  the  company. 
Finally  the  vein  was  struck  and  sunk  upon  for  about 
ninety  feet,  after  which  work  was  suspended  until  the 
Phoenix  Company  took  charge  of  the  property  in  the 
autumn  of  1850.  This  company  continued  operations 
along  the  vein,  which  still  ran  under  the  river,  until 
February,  1853,  when  they  abandoned  it.  The  trouble 
from  water,  especially  during  freshets,  was  so  great  that 
it  was  impossible  to  work  to  any  advantage  and  besides 
that,  the  vein,  away  from  the  river,  was  too  narrow  for 
profitable  mining.  The  principal  shaft  was  sunk  to  a 
depth  of  about  264  feet,  and  three  levels  driven  between 
500  and  600  feet.  The  vein-stone  consisted  of  calc-spar 
with  jasper  and  argillaceous  matter  and  contained  copper 
in  fine  particles  and  masses,  some  of  which  weighed 
1200  pounds,  together  with  silver. 

In  June,  1853,  a  thorough   examination  of  the  pro- 
perty was  commenced,  and  finished  in  1854.      From 


232  MINES  OF  COPPER. 

Samuel  W.  Hill's  report,  dated  January  5th,  1855,  the 
following  particulars  are  taken. 

The  property  of  the  company  is  1701  acres,  having 
in  its  northwest  part,  the  port  of  Eagle  river.  The  land 
declines  towards  the  Lake,  its  altitude  rarely  exceeding 
550  feet  above  the  level  of  the  water,  and  averaging  not 
more  than  350  feet.  The  banks  of  Eagle  river,  (which 
runs  through  it,)  vary  in  elevation,  being,  in  some  places 
high  and  precipitous,  in  others  low  and  easily  accessi- 
ble. 

The  band  of  rock  near  the  lake  is  conglomerate.  It 
is  succeeded  to  the  southward  by  alternating  beds  of  sand- 
stone and  trap,  having  a  dip  of  25°  towards  the  lake. 
Below  these  are  various  beds  of  trap  terminated  by  a 
hard,  light  blue  columnar  trap.  Underneath  this  is  a  bed 
which  is  composed  mostly  of  an  ash,  thin  bands  of  trap 
and  sand  stone,  and  rounded  scoriaceous  bodies  of  trap  or 
lava.  This  mass  is  cupriferous  and  between  it  and  the 
stratum  last  named  a  slide  has  taken  place.  In  some 
places  the  dislocation  has  been  sufficiently  great  to  pro- 
duce open  spaces  between  the  walls,  which  have  been 
filled  up  with  vein-minerals.  There  are  ancient  excava- 
tions in  this  bed,  and  it  is  in  some  places  well  filled  with 
copper.  Below  this  is  a  greenish  gray  trap  in  which  the 
principal  excavations  of  the  old  mine  were  made.  This 
is  succeeded  by  several  beds  of  trap,  followed  by  a  belt 
of  crystalline  trap  or  greenstone,  the  veins  traversing 
which  are  well  filled  with  copper.  After  this  come  sev- 
eral beds  of  trap,  ending  in  a  soft  porous  band,  which 
overlies  the  series  of  dark  colored,  close-grained  trap 
layers  in  which  the  Cliff  mine  is  worked.  After  these 


MINES  OF  COPPER.  233 

comes  a   columnar  trap,  poor  in   copper,  and  then  an 
amygdaloid  which  promises  well  for  that  metal. 

These  beds  do  not  all  contain  copper.  As  elsewhere 
in  this  region,  there  are  distinct  metalliferous  zones. 
The  chief  of  these  is  the  series  worked  in  the  Cliff  mine. 
Next  in  importance  is  the  ash  or  scoriaceous  bed,  which 
was  at  first  thought  remarkable  for  having  the  copper 
diffused  through  the  rock  and  not  in  a  vein.  Subse- 
quently, however,  it  has  been  stated  that  this  scoriaceous 
bed  is  a  true  east  and  west  vein. 

There  are  several  veins  on  this  property,  the  Ward 
vein,  the  Forster  vein,  the  Armstrong  vein,  the  East 
Phoenix  vein  and  several  others  which  have  not  been 
named.  The  workings  already  described  were  upon  the 
old  Phoenix  vein.  Attempts  were  made  to  renew  work 
on  this  vein  in  1855,  but  finally  discontinued  on  account 
of  the  old  trouble  with  water.  The  Armstrong  vein 
was  worked  in  1851  and  1852,  but  was  found  to  be  poor 
in  copper.  The  East  Phcenix  vein  was  discovered  in 
1852  and  the  following  season,  a  mass,  weighing  2,390 
pounds,  was  taken  out  quite  near  the  surface.  In  1855, 
the  principal  working  was  on  the  "ash  bed."  About 
five  tons  were  sent  to  Boston  in  November  of  that  year, 
and  smelted  at  the  Revere  Works.  The  metal  was  found 
to  contain  a  large  amount  of  silver,  the  poorest  speci- 
mens being  reported  as  worth  $100  a  ton  for  that  metal. 
The  prospects  of  the  company  are  now  good. 

The  entire  amount  expended  here  cannot  be  much 
short  of  $200,000,  and  there  are  few  places  upon  Lake 
Superior  which  show  more  abundant  indications  of  cop- 
per. 

20* 


234  MINES  OF  COPPER. 

The  mines  on  the  southern  side  of  the  greenstone 
bluffs  are  very  well  situated  for  working.  They  have 
never  been  opened  to  any  extent  in  the  greenstone,  but 
close  to  the  conglomerate  belt  which  divides  the  amyg- 
daloid from  that  rock,  they  are  as  productive  as  any- 
where else.  In  the  neighborhood  of  the  Cliff  mine  the 
position  is  less  favorable  for  adit  draining.  Towards 
the  eastern  extremity  of  the  Point,  the  amygdaloid  rises 
sufficiently  to  give  from  one  to  two  hundred  feet  of  back 
above  the  adit  level.  Frequently  the  productive  rock  is 
so  covered  with  drift  that  the  veins  can  only  be  discov- 
ered by  tracing  them  down  from  the  greenstone  and 
opening  shode  pits  on  their  supposed  course.  This  is 
the  reason  why  so  many  ineffectual  attempts  were  made 
to  find  productive  veins  in  the  greenstone  and  other 
more  exposed  rocks. 

The  Keweenaw  Point  Copper  and  Silver  Mining 
Company  was  formed  in  England,  and  has  discovered 
four  or  five  veins,  but  has  not  worked  them  yet  to  any 
extent. 

The  Star  Mining  Company  has  sunk  several  shafts 
and  abandoned  them.  During  the  summer  of  1853, 
they  discovered  a  new  vein,  which  is  said  to  promise 
well. 

The  Manitou  Mining  Company  commenced  opera- 
tions in  1852.  They  have  two  veins,  neither  of  them 
large  nor  very  productive. 

The  Iron  City  Mining  Company  deserves  notice  here 
as  a  warning  to  future  speculators  on  the  minerals  in 
this  region.  They  have  a  wide  and  regular  vein-  of  cal- 
careous spar,  cleaving  into  large  rhombohedra,  and  con- 
taining no  copper.  This  kind  of  vein,  when  unaccom- 


MINES  OF  COPPER.  235 

panied  by  quartz  and  the  zeolitic  minerals,  is  always 
barren  in  the  Lake  Superior  mining  region. 

The  Northwest  Mining  Company  of  Michigan,  being 
one  of  the  most  extensive,  demands  the  special  examina- 
tion of  those  who  are  interested  in  the  mineral  develop- 
ments of  this  district.  In  1849,  it  took  the  place  of  a 
company  which  had  been  mining  in  a  small  way  since 
1847.  They  have  three  veins,  the  Stoutenburgh,  Kelly 
and  Hogan  veins.  The  first  contains  the  principal  mine, 
and  has  a  course  of  north  16J°  east.  The  Hogan  runs 
north  19°  west,  and  the  two  would,  consequently,  inter- 
sect about  320  feet  south  of  the  mouth  of  the  adit  level  on 
the  Stoutenburgh.  The  third  or  Kelly  vein  has  a  course 
nearly  parallel  with  that  of  the  Hogan,  but  is  not  very 
well  defined. 

The  first  named  vein  has  been  opened  by  four  shafts, 
the  engine  shaft  being  500  feet  deep.  The  longest  level 
driven  is  about  1,000  feet.  The  whole  amount  exca- 
vated by  sinking  shafts  is  1,130  feet;  by  driving  levels, 
5,450  feet;  and  the  number  of  fathoms  stoped  is  about 
2,780.  The  vein  is  from  six  to  eighteen  inches  wide, 
the  average  width  being  about  a  foot.  The  lode  consists 
of  clayey  and  sandy  matter,  with  occasional  strings  of 
calc  spar,  and  does  not  look  very  promising.  It  contains 
but  .a  small  amount  of  stamp-work  and  that  of  a  poor 
quality,  but  masses,  weighing  from  a  few  hundred  pounds 
up  to  several  tons  are  frequently  met  with.  One  of 
eleven  tons  weight  was  taken  from  the  twenty  fathom 
level.  A  great  deal  of  that  which  is  taken  from  the 
shaft  is  amygdaloidal  trap  containing  shot  copper;  and 
it  is  worthy  of  remark  that  the  rock  in  the  vicinity  of 
the  vein  is  often  richer  in  metal  than  the  lode  itself. 


236  MINES  OF  COPPER. 

The  large  masses  appear  to  make  outside  of  the  lode 
but  close  to  it,  impoverishing  it  for  some  distance  in 
every  direction. 

The  works  on  the  Hogan  vein  are  much  less  extensive, 
but  the  vein  is  more  promising,  containing  less  argilla- 
ceous matter  and  being  more  crystalline.  It  has  produced 
small  masses  and  barrel-work  as  well  as  stamp-work. 

This  company  is  the  only  one  that  has  kept  accurate 
and  reliable  accounts  of  the  produce  of  the  stamps  and 
the  expenditures  per  ton.  From  this  report,  it  appears 
that  the  average  percentage  of  the  rock  when  carried  to 
the  stamps  is  1.34  of  copper,  so  that  a  ton  contains  27.4 
pounds  of  copper.  The  entire  cost  of  working,  after 
the  ground  has  been  opened  for  stoping,  is  §4.42  per 
ton,  and  the  value  of  a  ton,  after  deducting  expenses  of 
transportation,  is  $6.97.  Hitherto,  however,  the  re- 
ceipts of  the  mine  have  fallen  short  of  its  expenditures. 
The  value  of  copper  exported  has  lately  averaged  over 
$53,000  per  annum,  and  the  expenses  $77,000. 

We  believe  that  this  mine  has  now  suspended  opera- 
tions. 

The  Waterbury  Mining  Company  is  another  example 
of  failure  in  consequence  of  want  of  knowledge  of  the 
laws  which  regulate  the  metallic  deposits  of  Lake 
Superior.  It  was  opened  in  a  chloritic  mass  interposed 
between  the  conglomerate  and  the  greenstone,  and  the 
contact  of  these  last  named  rocks  has  never  been  found 
to  yield  copper  in  this  region. 

The  North  Western  Mining  Company  of  Detroit,  works 
the  same  vein  which  on  the  opposite  side  of  the  crystal- 
line trap  is  known  as  Copper  Falls  Vein.  Its  gangue 
is  quartzose  and  chloritic,  containing  crystals  of  analcime 


MINES  OF  COPPER.  237 

and  of  reddish  feldspar.  Its  average  width  is  three  feet. 
In  the  ten  fathom  level,  a  mass  of  copper  twelve  feet 
long  and  three  feet  high  has  been  discovered. 

The  Cliff  Mine  *  is  the  most  famous  of  all  the  work- 
ings on  Lake  Superior,  being,  indeed,  the  first  mine  in 
the  United  States,  excepting  those  of  coal  and  iron, 
which  was  extensively  and  systematically  wrought.  It 
is  also  the  first  mine  ever  opened  in  the  world  upon  a 
vein  bearing  copper  exclusively  in  the  native  state. 

In  1843  a  Mr.  Raymond  obtained  several  leases  in 
this  region,  three  of  which  he  conveyed  to  parties  in 
Pittsburg  and  Boston,  who  commenced  mining  in  the 
summer  of  1844.  The  first  work  was  done  in  the  autumn 
of  1844,  upon  the  outcrop  of  a  cupriferous  vein  at  Cop- 
per Harbor,  known  to  the  voyageurs  as  the  "green 
rock."  On  clearing  away  on  the  opposite  side  of  the 
harbor,  where  Fort  Wilkins  now  stands,  numerous  boul- 
ders of  black  oxyd  of  copper  were  found,  evidently  be- 
longing to  a  vein  near  at  hand,  which  was  discovered  in 
December,  and  proved  to  be  a  continuation  of  that 
worked  during  the  summer. 

Mining  was  commenced  here  immediately;  two  shafts 
were  sunk  100  feet  apart,  and  a  goodly  quantity  of 
black  oxyd  of  copper,  mixed  with  silicate,  was  taken  out. 
This' was  remarkable,  as  being  the  only  known  instance 
of  a  vein  containing  this  as  the  principal  ore.  Unfor- 
tunately, this  was  but  a  rich  bunch,  which  gave  out  at 
the  depth  of  a  few  feet,  although  the  vein  continued. 
The  gangue  was  chiefly  calcareous  spar,  mixed  with 
some  argillaceous  and  quartzose  matter.  Fine  crystals 
of  analcime,  as  well  as  of  native  copper  and  the  red 
*  Owned  by  the  Pittsburg  and  Boston  Mining  Company. 


238  MINES  OF  COPPER. 

oxyd  were  found  in  it.  About  30  or  40  tons  of  black 
oxyd  were  obtained  and  sold  for  $4,500.  The  main 
shaft  was  continued  down  120  feet  and  levels  driven 
each  way,  for  a  considerable  distance,  without  finding 
another  bunch  of  ore,  so  that  in  1845  the  company 
determined  to  explore  their  extensive  property.  In 
August,  of  that  year,  the  Cliff  Vein  was  discovered. 

This  vein  was  first  observed  on  the  summit  and  face 
of  a  bluff  of  crystalline  trap,  rising  nearly  200  feet 
above  the  valley  of  Eagle  River.  The  break  or  depres- 
sion made  by  it  in  the  back  of  the  ridge  was  quite  dis- 
tinct, and  has  since  been  traced  to  the  lake,  and  found 
marked  by  ancient  excavations.  At  the  summit  of  the 
bluff,  it  appeared  to  be  a  few  inches  wide,  and  contained 
native  copper  and  specks  of  silver  incrusted  with  capil- 
lary red  oxyd.  Half  way  down  the  cliff  it  had  expanded 
to  a  width  of  over  two  feet,  and  consisted  of  numerous 
bunches  of  laumonite,  with  a  small  per  centage  of  copper 
finely  disseminated  through  it. 

As  the  vein  appeared  to  widen  in  its  descent,  by  the 
direction  of  Mr.  Whitney  a  shaft  was  sunk  a  few  feet  a 
little  below  the  edge  of  the  bluff,  and  a  level  driven  into 
the  greenstone  for  a  short  distance.  Nothing  of  impor- 
tance, however,  was  done  till  the  talus  at  the  base  of  the 
cliff  was  cleared  away,  and  the  vein  traced  into  the 
amygdaloid.  A  level  was  then  driven  in  upon  it,  and 
at  a  distance  of  70  feet  the  first  mass  of  copper  was 
struck. ' 

The  beds  of  the  rock  dip  at  about  66°  to  the  north, 
so  that  the  extent  of  the  mine  in  that  direction,  the 
vein  being  opened  to  the  south  of  the  greenstone,  is 
continually  increasing  as  each  successive  level  is  opened. 


MINES  OP  COPPER.  239 

To  the  south,  the  mine  is  limited  by  the  extent  of  the 
company's  property.  The  longest  level,  244  feet  below 
the  adit  had  been  extended  at  the  date  of  Whitney's  de- 
scription, 600  feet  to  the  south  of  the  lower  shaft,  and 
the  supposed  distance  to  the  greenstone  is  900  feet. 
Each  level  extends  in  this  direction  about  100  feet  fur- 
ther than  the  one  66  feet  above. 

The  mine  was  formerly  worked  through  two  shafts, 
less  than  100  feet  apart;  but  during  the  winter  of 
1853-4,  a  third  had  been  sunk  to  level  No.  1,  from  the 
upper  edge  of  the  bluff,  a  distance  of  138  feet.  The 
engine-shaft,  in  1854,  had  reached  the  ninth  level,  a 
depth  of  444  feet  below  the  adit,  and  the  entire  depth 
from  the  collar  of  the  third  shaft  to  the  ninth  level  will 
be  630  feet. 

"  The  remarkable  and  uniform  richness  of  the  vein 
may  be  inferred  from  the  fact  that  no  part  of  it  is  so 
poor  as  not  to  be  worth  taking  down ;  and  so  far  as  the 
work  has  been  carried,  hardly  a  fathom  of  ground  has 
been  left  standing  on  it.  On  calculating  the  number  of 
fathoms  of  the  vein  removed  in  the  drifts,  shafts  and 
stopes,  I  find  it  to  be,  approximately,  8,270;  and  there 
has  been  produced  an  average  amount  of  761  pounds  of 
copper  per  fathom — a  result  which  is  truly  astonishing, 
when'  it  is  considered  that  the  whole  of  the  vein  has 
been  taken  down."* 

It  runs  about  north  27°  west,  and  its  underlay  is  about 
10°  to  the  east,  but  in  its  lower  levels  the  dip  varies 
somewhat.  In  some  places  it  is  three  or  four  feet  wide, 
in  others,  only  a  few  inches;  its  average  width  is,  prob- 
ably from  fifteen  to  eighteen  inches.  The  vein-stone  is 
*  Whitney's  metallic  wealth  of  the  United  States. 


240  MINES  OF  COPPER. 

quartz,  calcareous  spar,  and  the  zeolitic  minerals,  and 
it  abounds  in  fine  crystallizations. 

Its  metallic  contents  are  exclusively  native  copper 
and  silver.  The  copper  occurs  in  masses  of  great  size, 
from  a  few  hundred  pounds  up  to  nearly  a  hundred  tons ; 
and  the  vein  is  not  only  rich  in  these,  but  also  furnishes 
a  large  quantity  of  stamp-work,  containing  an  unusually 
high  per  centage  of  copper. 

At  the  date  of  the  last  report,  shaft  No.  4,  had 
reached  a  depth  of  251  feet.  The  second  shaft  was 
sinking  from  the  70  to  the  80  fathom  level,  at  which  it  was 
expected  to  cut  the  vein.  The  extension  of  this  shaft 
will  be  much  deeper,  if  the  productive  stratum  recently 
discovered  at  the  North  American  mine  be  sought  for. 
This  will  not  be  reached  at  a  less  depth  than  950  feet 
from  the  adit  level. 

Besides  this  main  vein,  and  its  droppers,  there  are 
several  others  on  the  property.  The  west  vein,  which 
was  formerly  supposed  to  be  a  mere  divergence  of  the 
old  vein,  upon  one  of  its  numerous  floors  of  amygdaloid, 
has  been  found  to  be  a  distinct  and  separate  lode,  very  rich 
in  copper.  The  East  Cliff  vein,  about  40  rods  east  of  the 
present  workings  has  been  opened  and  seems  to  promise 
well.  About  270  feet  west  of  the  main  vein,  there  are 
surface  indications  of  a  very  large  lode,  measuring  from 
four  to  five  feet  in  width.  It  is  intended  to  open  this 
by  a  cross  cut  from  the  30  fathom  level. 

The  operations  of  this  mine  will  be  seen  by  the  fol- 
lowing table,  compiled  from  Whitney's  book,  and  the 
printed  reports  of  the  Directors,  the  original  amount  of 
capital  stock  paid  in  by  the  Shareholders  being  only 
$110,905,00. 


MINES  OF  COPPER. 


241 


OO 

00 

00 

00 

00 

00 

on 

t) 

Oi 

i 

s 

CO 

po 

^ 

c»  &  ^ 

« 

g 

1C 

tO 

1—  ' 
OO 

§ 

i 

s 

OS   bO   ^ 
OS   Oi   CO 

« 

o» 

(O 

OS 

-T 

CO 

LO 

4- 

I—  i   Oi   O 

M 

CO 

£ 

GO 

OS 
00 

CC1 

§ 

00   ^I   § 

1 

. 

to 

OO 

Oi 

1—  ' 

^J 

C7» 

— 

O   rf^-   -4 

* 

CO 

1—  1 

1—  1 

*• 

^^ 

LO 

OS 

Oi   O   OS 

to 

to 

to 

h— 

h-  ' 

M 

to 

^ 

% 

• 

M 

to 

OS 

2 

Oi 

C7» 

L<, 

to 

OO 

2 

b^ 

O   CO 

'o    5 

Oi 

to 

CO 

0 

00 

o« 

d 

CO 

GO   CO 

o   a 

OO 

OS 

"_ 

CO 

4- 

PA 

o 

*co 

OO 

~T  ^  ' 

cc*    *3 

CO 

-jr 

to 

CO 

o 

OS 

ffl 

|—» 

§ 

s 

•s— 

00 

--1  •<! 

-I—   I—1 

p 

. 

OS 

Oi 

^ 

^ 

Oi 

*» 

Oi 

OJ 

m 

CO   OS 

1 

• 

LO 

OS 

—^J 

o 

Oi 

OS 

OS 

o 

OS 

GO   O 

w 

Oi 

CO 

CO 

o 

CO 

;o 

t—  ' 

tc 

CO 

f  . 

§ 

• 

OS 

CO 

f* 

'bo 

M 

h-i 

00 

00 

J- 

I  p 

— 

"-•J 

:—  i 

GO 

CO 

1  I 

CO   I—" 

p 

4— 

Cn 

h—  » 

^o 

OS 

4-* 

to 

o 

^J   CO 

*j 

s 

CO 
00 

to 

OO 

00 

CO 

o 

00 
OS 

c: 
Oi 

5 

1 

00 
CO 

OS   CO 
Oi   CC 

I 

> 

. 

~4 

bi 

CO 

r-^ 

i~{ 

^~J 

Oi 

^! 

-I 

^ 

Oi 

o 

to 

>£»• 

-^1 

Oi 

o 

o 

oc  to 

s 

CO 

—I 

05 

b 

CO 

o 

to 

4- 

CD 

00   CO 

H 

g 

CO 

§ 

-4 

O   GO 

1 

to 

o 

o 

o 

CO 

CO 

o 

o 

CO 

CO   -<l 

5 

OS 

Oi 

OO 

OS 

A 

4- 

*a 

LO 

Oi   O 

i 

^ 

9 

o 

CO 

00 

Oi 

o 

0 

4- 

o 

4 

§ 

§ 

o 

o 

8 

0 

o 

o 

0 

s 

§ 

B1  « 
s  ^ 

OO 

o 

OS 

i 

s 

s 

00 

oa 

OS 

o 

I 

§ 

o 

00 

~  > 

1 

to 

GO 

go 

co 

I—1 

bo 
M 

o 

§ 

1 

21 


242  MINES  OP  COPPER. 

The  amount  of  silver  taken  out  varies.  It  is  always 
found  in  pockets,  and  never  alloyed,  to  any  extent,  with 
the  copper,  even  at  the  point  of  contact.  The  most 
usual  mineral,  accompanying  the  silver,  is  a  greenish 
magnesian  substance,  apparently  talc.  In  the  Hill  vein, 
a  small  quantity  is  found  in  the  smelted  copper  a  few 
ounces  to  the  ton — not  enough  to  justify  its  separation. 
At  the  Cliff  mine,  the  largest  quantity  of  this  metal  ob- 
tained  in  one  year  was  nearly  35  pounds  troy.  It  is 
picked  out  by  hand  from  the  coarse  metal  which  is  taken 
from  under  the  stamp-heads. 

The  North  American  is  another  old  company,  and  has 
mined  extensively  at  two  points.  The  "Old  North 
American  Mine"  was  opened  in  1846,  and  worked  till 
the  spring  of  1853,  when  it  had  reached  the  depth  of 
415  feet.  The  course  of  the  principal  vein  is  north  58° 
west,  and,  therefore,  not  parallel  with  the  productive 
veins  of  the  formation.  During  the  four  last  years  it 
was  worked,  it  yielded  446,000  pounds  of  pure  copper. 
The  entire  expenditures  upon  it  were  $  200,000. 

In  1852  this  company  opened  the  South  Cliff  mine, 
on  an  extension  of  the  famous  Cliff  vein.  Up  to  Feb- 
ruary of  1854,  715  feet  had  been  opened  in  driving,  76 
feet  in  cross-cutting,  438  feet  in  sinking  in  rock,  and 
106  fathoms  had  been  stoped.  From  these  workings 
the  extraordinary  amount  of  506,000  pounds  had  been 
taken,  yielding  an  average  of  67|  per  cent,  of  copper. 

At  this  mine,  on  the  4th  of  July,  1853,  was  thrown 
down  the  largest  mass  of  native  copper  ever  before  found 
on  Lake  Superior.  It  was  40  feet  long,  20  high,  and  2 
thick.  Its  weight  was  estimated  at  from  150  to  200 
tons. 


MINES  OF  COPPER.  243 

The  vein-stone  of  this  mine,  near  the  surface,  furnished 
fine  specimens  of  prehnite  with  crystallized  copper. 
Its  workings  extend  further  south  of  the  green-stone 
than  those  of  any  other  mine  of  the  region.  At  first  the 
vein  seemed  to  he  impoverished  in  that  direction,  hut  as 
they  advanced  further,  it  began  to  improve. 

The  Albion  Mining  Company  sunk  a  shaft  on  this 
point,  in  the  same  geological  position  as  the  Cliff  Mine, 
to  the  depth  of  200  feet,  but  finally  abandoned  their 
work  for  want  of  encouragement,  in  1852. 

The  Fulton  Mining  Company  commenced  operations 
on  an  old  working  in  1853,  and  have  taken  out  a  great 
deal  of  copper.  In  one  part  of  the  mine,  the  vein 
yielded  a  ton  of  copper  to  the  fathom.  The  vein-stone 
is  remarkable  for  containing  much  epidote,  mixed  with 
calcareous  spar. 

In  addition  to  the  veins  already  explored  or  worked 
by  companies,  there  have  been  others  discovered  upon 
this  point.  They  are  held  by  individuals,  and  have 
only  been  opened  for  exploration. 

The  geological  character  of  ISLE  ROYALE  resembles 
that  of  Keweenaw  Point.  The  ridges  of  trap  traverse 
the  island  longitudinally,  and  this  rock,  with  its  intercal- 
ated conglomerate,  forms  the  entire  island.  The  strata 
dip  in  a  direction  opposite  those  on  the  point,  and  their 
mural  faces  look  towards  the  north.  The  beds,  however, 
differ  from  those  in  being  thinner,  so  that  the  metallifer- 
ous veins  are  subject  to  frequent  changes  in  passing 
from  one  stratum  to  another.  Great  hopes  were  formed 
of  this  island  at  the  opening  of  the  Lake  Superior  region, 
and  soon  afterwards  nearly  all  of  it  had  been  taken  up 
by  different  companies. 


244  MINES  OF  COPPER. 

The  veins  are  differently  situated  with  regard  to  the 
strata,  some  being  at  right  angles  and  some  parallel  to 
their  dip.  Epidote  belts,  filled  with  fine  particles  of 
native  copper,  are  found  here,  but  they  have  not  been 
found  sufficiently  persistent  in  metalliferous  contents  to 
be  profitably  worked.  In  1853,  nearly  all  the  mines 
were  abandoned,  only  two  being  wrought  and  those  on  a 
small  scale. 

The  Siskawit  Mine  has  been  extensively  worked,  and 
was  at  first  quite  productive.  On  sinking  but  a  short 
distance,  however,  a  hard  basaltic  rock  was  encountered, 
in  which  the  vein  contracted  to  a  mere  fissure.  After 
traversing  this,  the  vein  improved,  but  not  sufficiently 
to  pay  for  working  it,  especially  as  it  was  necessary  to 
carry  the  workings  under  the  lake,  since  the  rocks  dip 
in  that  direction. 

The  Pittslurg  and  Isle  Royale  Mining  Company  has 
worked  a  narrow  vein  rich  in  copper,  which  traverses  a 
crystalline  rock.  Their  machinery  is  "  miserably  de- 
fective," and  their  operations  consequently  impeded. 

The  ONTONAGON  MINING  DISTRICT  receives  its  name 
from  the  principal  river  which  drains  it.  This  stream 
has  three  branches,  one  coming  from  the  east,  another 
from  the  west,  and  the  third  from  the  south.  Uniting, 
they  cross  the  Trap  Range  at  right  angles  to  its  course. 

The  mines  are  on  the  range,  and  are  worked  at  va- 
rious points  for  a  distance  of  twelve  miles  on  each  side 
of  the  river,  making  the  entire  length  of  the  district 
about  twenty-four  miles.  The  cupriferous  deposits  here 
differ  from  those  on  Keweenaw  Point  in  their  being 
parallel  to  the  line  of  strike  of  the  formation. 

The  character  of  the  trappean  rocks  also  differs  from 


MINES  OF  COPPER.  245 

that  which  they  exhibit  upon  the  point.  The  varieties 
of  rock  are  more  numerous  and  epidote  almost  always 
occurs  where  copper  is  found.  West  of  the  Ontonagon,  a 
large  part  of  the  range  on  the  north  is  made  up  of  reddish 
quartzose  porphyry,  which  appears  to  be  entirely  barren 
of  copper.  The  layers  of  conglomerate  are  imbedded 
in  the  trap,  and  to  the  north  it  is  flanked  by  heavy  beds 
of  this  rock.  There  is  no  marked  belt  of  unproductive 
crystalline  rock  here,  and  the  position  of  the  bed  and 
veins,  with  regard  to  any  fixed  line  of  upheaval,  is  not 
so  well  ascertained.  Copper  is  abundantly  diffused 
through  the  district,  but  mining  is  not  so  profitable  here 
on  account  of  there  being  less  concentration  of  the  metal 
in  limited  spaces. 

The  copper  occurs  in  four  forms  of  deposite  :  1.  Indis- 
criminately scattered  through  the  beds  of  trap.  2.  In 
contact  deposits  between  the  trap  and  sandstone  or  con- 
glomerate. 3.  In  seams  and  courses  parallel  with  the 
bedding  of  the  rock,  and  having  the  nature  of  segregated 
veins.  4.  In  true  veins  coinciding  in  direction  with  the 
beds  of  rock,  but  dipping  at  a  different  and  usually  a 
greater  angle,  in  the  same  direction  as  the  formation. 

Deposits  of  the  first  class  are  common,  and  have 
been-  worked  but  with  poor  success.  Masses  of  many 
hundred  pounds  weight  have  been  repeatedly  found  in 
the  trap,  without  any  connection  with  a  vein  fissure, 
and  sometimes  unaccompanied  by  vein-stone.  When 
smaller,  the  particles  of  metal  usually  fill  amygdules  in 
the  rock,  and  are  most  abundant  along  the  line  of  junc- 
tion of  two  beds  of  different  character. 

Contact  deposits  have  produced  well  in  this  district, 
21* 


246  MINES  OF  COPPER. 

though  further  working  is  requisite  to  test  their  perma- 
nent value.  When  they  occur  between  the  sandstone 
and  the  trap,  they  are  not  worth  much,  as  they  soon  lose 
their  metallic  contents.  The  deposits  which  are  found 
between  the  trap  and  the  conglomerate  appear  to  belong 
to  this  class,  but  have  some  of  the  features  of  true  veins. 
In  this  position  great  masses  of  copper  are  accumulated 
near  the  surface,  and  even  at  considerable  depths 
below  it. 

The  third  class  of  deposit,  in  segregated  veins,  is 
peculiar  to  this  district.  Occasionally  the  vein  is  irreg- 
ular in  its  course,  being  suddenly  heaved  to  one  side  or 
the  other,  or  disappearing  altogether.  In  these  cases, 
the  metallic  matter  seems  to  be  accumulated  in  parallel 
courses,  coinciding  with  the  bedding  of  the  rocks,  but 
irregular  in  the  extent  and  distribution  of  their  metallic 
and  mineral  contents.  Sometimes  they  run  into  each 
other,  both  horizontally  and  vertically,  giving  rise  to 
the  so-called  feeder  veins;  frequently  they  diminish  to  a 
mere  seam  destitute  of  both  veins  and  metal,  and  on 
cross-cutting  another  seam  is  struck,  often  well  filled 
with  copper. 

The  true  veins  are  not  numerous.  They  coincide 
with  the  line  of  bearing  of  the  rocks,  but  in  following 
them  down,  they  are  found  to  be  wholly  independent. 
They  are  often  rich  in  copper,  and  may  be  confidently 
worked. 

The  Douglass  Houghton  Mine  was  worked  on  a  small 
scale  in  1846,  but  it  was  not  till  1850  that  it  was  prose- 
cuted with  any  energy.  The  vein  at  the  surface  was 
between  two  and  three  feet  wide,  quartzose,  and  well  filled 


MINES  OF  COPPER.  247 

with  copper.  There  it  had  well  defined  walls  with  sel- 
vages of  argillaceous  matter,  and  a  gangue  distinct  from 
the  rock.  On  descending,  however,  it  was  found  to  be 
irregular,  in  some  places  wide  and  well  charged  with  cop- 
per, in  others  entirely  lost.  There  is  a  break  or  fault 
which  has  displaced  it  fourteen  feet.  In  the  winter  of 
1853-4,  the  vein  had  widened  again. 

The  Toltec  Consolidated  Mine  was  opened  in  1850, 
and  up  to  March,  the  deepest  shaft  had  been  sunk  210 
feet.  Two  levels  have  been  driven  and  several  cross-cuts 
made.  A  mass  of  a  ton  weight  has  been  discovered,  but 
the  distribution  of  metal  in  the  vein  is  so  irregular  that 
no  conclusion  can  be  formed  as  to  the  probable  success 
of  the  mine. 

The  Aztec  Mining  Company  have  been  carrying  on 
excavations  in  the  face  of  a  bluff,  which  had  been  very 
extensively  worked  over  by  ancient  miners.  The  copper 
is  scattered  indiscriminately  through  the  rock,  in  lumps 
and  small  masses.  In  1853  operations  were  suspended. 

The  Bohemian  Mining  Company  works  on  what  is 
called  the  "Piscataqua  location."  It  is  difficult  to  trace 
any  regular  vein  here,  but  there  is  an  epidote  seam  which 
is  rich  in  copper. 

The  Adventure  Mining  Company  has  made  many 
extensive  but  irregular  excavations  in  the  face  of  a  bluff, 
in  which  there  is  no  regular  vein.  It  is  a  crystalline 
and  compact  trap  having  copper  and  silver  scattered 
through  it.  In  spite  of  the  irregularity  of  the  workings, 
a  considerable  quantity  of  copper  has  been  taken  out. 

The  Minnesota  Mine  is  the  most  productive  on  the 
Ontonagon,  and  second  only  to  the  famous  Cliff  Vein. 


248  MINES  OF  COPPER. 

It  was  discovered  in  the  winter  of  1847-8,  and  found  to 
contain  excavations  of  the  ancient  miners,  who  had  sep- 
arated a  mass  of  copper,  weighing  over  six  tons,  and 
then  abandoned  it  as  too  bulky  for  removal  by  the  means 
at  their  command,  leaving  their  stone  hammers  behind 
them. 

Eight  principal  shafts  have  been  opened  on  the  vein 
and  the  South  Lode,  following  its  dip,  which  varies  52°  to 
64°  to  the  north,  that  of  the  rocks  being  44°  in  the 
same  direction.  The  gangue  is  quartz,  calcareous  spar 
and  epidote,  and  the  walls  well  defined,  although  in  some 
places  not  very  regular.  They  are  usually  smooth, 
sometimes  striated,  but  generally  destitute  of  selvages 
and  flucan.  Near  the  walls,  thin  lenticular  sheets  of 
mixed  calcareous  spar  and  laumonite  are  frequently 
found  overlapping  one  another. 

The  last  printed  report  (March  1st,  1856,)  states 
that,  during  the  year,  the  shafts  had  been  sunk  in  the 
aggregate  308  feet,  and  winzes  to  the  amount  of  418 
feet  opened,  making  the  total  depth  of  sinking  in  shafts 
and  winzes  on  January  1st,  1856,  2516  feet.  The 
deepest  shaft,  No.  2,  had  at  that  time  reached  the  60 
fathom  level,  447  feet  from  the  surface.  The  extent  of 
drifting  for  the  same  period  was  3022  feet,  the  whole 
extent  of  the  six  levels  on  January  1st,  being  10,728 
feet.  The  longest  level  (No.  1)  had  been  opened  1663 
feet,  the  shortest  (No.  5)  436  feet.  These  openings  ex- 
posed about  117,642  superficial  square  feet  of  vein,  on 
which  the  amount  of  stoping  done  was  15,912  feet,  pro- 
ducing 890  Ibs.  of  mineral  per  fathom,  or  about  148  Ibs. 
per  foot,  stope  measure. 


MINES  OF  COPPER. 


249 


The  whole  extent  of  real  estate  owned  by  the  com- 
pany at  that  time  (including  115  acres  in  suit  between 
them  and  the  National  Mining  Company,)  was  2270 
acres.  During  the  year  1855,  several  masses  were 
taken  out,  one  of  which  weighing  5,738  Ibs.,  was  sent 
to  England  as  a  mineral  curiosity.  In  the  summer  of 
that  year,  a  mass  of  copper  was  exposed  in  the  10 
fathom  level  near  No.  5  shaft.  In  February,  1856,  the 
agent  reports  that  27  men  were  constantly  employed 
upon  it,  and  that  200  tons  of  copper  had  been  taken 
from  it,  but  that  they  had  not  yet  been  able  to  deter- 
mine its  extent. 

The  following  table  is  copied  from  the  same  report. 


Date. 

No.  of  men 
employed. 

Expendi- 
ture. 

Mineral 
product. 
Tons. 

Nett  value 
in  copper. 

Assessra'ts 
paid. 

Dividends 
paid. 

1848, 

20 

$14,000 

6* 

$1,700 

$10,500 

1849, 

60 

28,000 

52          14,000 

16,500 

1850, 

90 

58,000 

103 

29,000 

36,000 

1851, 

175 

88,000 

307£ 

90,000 

3,000 

1852, 

212 

108,000 

520 

196,000 

$30,000 

1853, 

280 

168,000 

523 

210,000 

60,000 

1854, 

392 

218,000 

763     ;  290,000 

90,000 

1855, 

471 

281,000   |     1,434 

550,000 

200,000* 

The  South  Lode  is  at  the  junction  of  the  trap  with  a 
bed  of  conglomerate,  which  crosses  the  Minnesota  tract 
a  short  distance  south  of  their  main  vein.  They  there- 
fore opened  it  in  1852,  by  driving  a  cross  cut  from  their 
adit  level.  Large  masses  of  copper  were  found  by  the 

*  During  this  year  the  stock  was  increased  to  20,000  shares,  par 
value,  $1,000,000. 


250  MINES  OF  COPPER. 

side  of  the  conglomerate,  whereupon  a  shaft  was  sunk 
in  this  neighborhood.  The  lode  was  found  to  be,  in 
some  places,  five  feet  wide,  and  filled  for  a  distance  of 
40  feet  with  a  mass  of  copper  almost  continuous.  Upon 
drifts  the  lode  is  very  rich,  carrying  masses  of  copper 
interspersed  with  a  good  deal  of  silver. 

The  Rockland  Mining  Company  is  at  work  on  lands 
which  originally  belonged  to  the  Minnesota  Company. 
It  was  formed  in  September  1853,  with  a  capital  stock 
of  $500,000  in  20,000  shares,  the  terms  of  agreement 
with  the  Minnesota  Company  being,  that  the  land  should 
be  put  in  at  $100,000.  It  was,  in  fact,  a  dividend  on 
Minnesota  stock. 

The  tract  belonging  to  the  new  company  adjoins  the 
Minnesota  lands,  and  appears  to  carry  across  its  entire 
breadth  (some  three  thousand  feet)  a  continuation  of  the 
veins  just  described.  Some  old  openings  were  found, 
and  explorations  in  these  were  so  promising  that  the 
work  was  begun  at  that  point.  An  adit  was  opened  on 
the  north  side  of  the  bluff.  At  a  distance  of  390  feet 
from  the  opening,  it  cut  the  north  vein  at  the  depth  of 
170  feet,  and  230  feet  further  it  lays  open  the  main 
and  the  south  lodes  at  about  the  same  depth.  At  the 
date  of  the  last  printed  report,*  four  shafts  had  been 
opened  and  sunk  to  a  depth  varying  from  80  to  130 
feet  in  depth,  and  a  fifth  had  been  commenced.  Three 
levels  had  been  opened,  one  72  feet  from  the  surface, 
the  adit  level  on  the  vein,  and  one  10  fathoms  below  it. 
Besides  this  a  cross  cut  had  been  driven  from  the  adit, 
which  reached  the  Minnesota  South  Lode,  at  the  distance 
*  May  1st,  1856. 


MINES  OF  COPPEK.  251 

of  275  feet  from  Rockland  vein.  Upon  this  drifts  were 
made  east  and  west,  stripping  the  vein  from  the  conglome- 
rate which  forms  the  foot  wall.  This  vein  is  about  two 
feet  thick,  and  is  said  to  be  good  "stamping  lode." 
Barrel-work  of  from  10  to  20  pounds  has  been  taken 
from  it.  At  a  distance  of  100  feet  south  of  the  Rock- 
land  vein,  this  same  cross-cut  opened  a  large  flat  vein, 
from  which  pieces  weighing  from  50  to  100  pounds  were 
taken.  At  shaft  No.  4,  a  mass  of  copper,  weighing 
30  tons,  and  bearing  unmistakable  marks  of  the  tools 
of  the  ancient  miners,  was  found  ;  from  the  adit  level  also, 
many  masses  have  been  taken,  some  of  which  weighed 
15  tons. 

This  is  considered  one  of  the  most  promising  mines 
on  the  lakes.  The  product  of  the  first  years  operations 
was  23  tons,  that  of  the  second  137  tons  of  70  per  cent. 

The  National  Mining  Company  in  1852,  opened  a 
vein  lying  between  the  conglomerate  and  trap,  in  the 
same  range  with,  but  at  some  distance  from  the  Minnesota 
property.  Ancient  mine- work  was  discovered  here,  con- 
sisting of  a  shaft  sunk  to  the  depth  of  about  50  feet, 
timbered  and  scaffolded.  A  nearly  continous  sheet  of 
copper  extended  down  its  side.  Work  was  prosecuted 
vigorously  during  the  following  winter,  and  the  next 
year  35,808  pounds  of  masses,  and  46,046  of  barrel- work, 
averaging  72  per  cent,  of  pure  copper,  were  shipped. 

In  January,  1854,  206  fathoms  had  been  stoped,  and 
2,307  fathoms  were  ready  for  that  operation.  The  vein 
is  remarkable  for  lying  between  two  dissimilar  forma- 
tions, and  for  containing  scarcely  any  veinstone,  being 
almost  one  solid  sheet  of  copper  for  a  considerable  dis- 
tance from  the  point  at  which  it  was  first  opened. 


252  MINES  OF  COPPER. 

The  Norwich  Mining  Company  has  a  regular  vein  of 
quartz,  containing  radiated  epidote,  native  copper  and 
red  oxyd.  The  workings  are  extensive  and  the  vein 
rich. 

There  are  many  other  mines  in  this  region  besides 
those  which  we  have  noticed ;  hut  those  we  have  named 
furnish  the  most  instructive  lessons  upon  the  nature  of 
veins  and  the  prospects  of  mining  in  this  vicinity.  We 
have  been  somewhat  full  in  regard  to  the  particulars  of 
these  workings,  but  we  do  not  feel  that  we  have  been 
unnecessarily  prolix,  as  the  Lake  Superior  region  is  so 
very  important,  the  mines  more  extensively  and  scienti- 
fically worked  than  any  of  the  same  metal  in  our  coun- 
try, and  much  misunderstanding  prevails  concerning 
them. 

Of  the  PORTAGE  LAKE  mining  district  we  have  little 
to  say.  The  mines  are  not  fully  developed ;  there  are 
few,  if  any,  regular  veins,  the  metal  being  found  dis- 
seminated through  beds  which  run  with  the  formation, 
and  differ  but  little  from  the  other  trappean  beds  with 
which  they  are  associated.  They  are  more  regular  in 
their  course,  and  more  uniform  in  their  contents,  than 
similar  deposits  on  the  Ontonagon  River.  Ancient  ex- 
cavations have  also  been  found  extending  over  a  great 
length  of  vein. 

The  great  value  of  the  Lake  Superior  district,  as  a 
mining  region,  may  be  gathered  from  Mr.  Whitney's 
table  of  the  yield  of  the  more  important  mines.  From 
this  it  appears  that  from  1845,  when  the  first  casual  ex- 
cavations were  made,  up  to  the  close  of  1853,  4,824 
tons  of  pure  copper  had  been  taken  from  these  mines, 
and  considerably  more  than  one-fourth  of  this  total  had 


MINES  OF  COPPER.  253 

been  sent  off  in  1853.  At  the  date  of  publication  of 
his  book  on  the  Metallic  Wealth  of  the  United  States, 
there  were  75  mines  at  work,  employing  2,800  men. 
The  entire  amount  expended  upon  the  whole  region,  up 
to  December  31st,  1853,  he  estimates  at  $4,800,000 ; 
and  the  value  of  copper  produced,  at  an  average  price 
of  25  cents  a  pound,  was  $2,700,000.  Of  this,  $504,000 
had  been  paid  out  in  dividends,  and  the  rest  applied  to 
the  further  development  of  the  mines.  Of  the  capital, 
a  considerable  portion  was  invested  in  mines  which  pro- 
mise remarkably  well,  but  which  had  just  been  opened 
at  the  time  the  above  estimate  was  made ;  a  great  deal 
of  it,  however,  was  thrown  away  during  the  wild  excite- 
ment which  characterized  the  first  reckless  speculations 
in  this  district.  The  mines  are  permanent,  and  what- 
ever may  be  the  fluctuation  in  the  market  prices  of  the 
stock  of  individual  companies,  there  can  be  no  doubt  of 
the  great  value  of  the  veins  of  the  region.  The  yield 
for  1854  was  estimated  by  Mr.  Whitney  at  2,000  tons 
of  pure  copper. 

The  trap  range  extends  into  Wisconsin,  but  no  valu- 
able veins  of  copper  have  yet  been  discovered  beyond 
the  borders  of  the  State  of  Michigan. 

On  the  northern  shore  of  the  lake,  in  Canada,  numer- 
ous companies  have  been  formed  and  have  attempted 
mining  in  the  trappean  rocks,  as  well  as  in  those  of  the 
azoic  period.  The  trap  appears  to  correspond  with  that 
of  the  south  range  on  Keweenaw  Point.  No  workings 
are  now  going  on  here,  but  from  1846  to  1849,  a  power- 
ful vein  was  wrought  on  Spar  Island  and  the  main  land 
opposite.  The  copper  occurs  in  the  form  of  pyrites  and 
22 


254  MINES  OF  COPPER. 

variegated  sulphuret,  but  the  ore  is  too  small  in  quantity 
to  be  worked.  Native  silver  and  sulphuret  of  zinc  have 
been  found  in  the  vein  on  the  mainland. 

On  Michipicoten  Island,  in  1846,  operations  were 
commenced  by  the  Quebec  and  Lake  Superior  Mining 
Association.  Formidable  preparations  were  made.  An 
adit  was  driven  200  feet,  three  shafts  sunk,  a  level  com- 
menced, and  smelting  furnaces  erected.  At  last,  after 
expending  $150,000,  they  discovered  that  there  was  no 
ore  to  smelt. 

On  the  north  shore  of  Lake  Huron,  veins  are  found  in 
a  white  sandstone  or  quartz  rock,  containing  sulphurets, 
chiefly  pyrites.  The  Bruce  Mine  is  situated  about  fifty 
miles  south  of  Saut  Ste.  Marie,  and  has  been  success- 
fully worked.  During  the  first  year  an  open  cut,  126 
feet  long  and  5  deep,  was  made,  from  which  240  tons  of 
ore  were  taken.  After  this  shafts  were  sunk,  smelting 
works  erected,  and  a  great  deal  of  money  wasted  on  un- 
profitable improvements.  In  spite  of  this  bad  manage- 
ment, however,  the  mine  pays  a  good  dividend,  and  is 
likely  to  do  still  better. 

ORES  OF  THE  MISSISSIPPI  VALLEY. 

In  the  Mississippi  Valley,  numerous  cupriferous  depo- 
sits occur  at  the  junction  of  the  lower  Silurian  limestone 
with  the  azoic  rocks.  They  are  often  found  in  connec- 
tion with  the  lead  ores  of  the  west,  which  they  resem- 
ble in  their  mode  of  occurrence. 

In  Wisconsin,  these  ores  lie  far  to  the  south  of  the 
trappean  rocks.  They  occur  chiefly  in  the  neighbor- 
hood of  Mineral  Point,  in  what  is  called  the  Ansley 


MINES  OF  COPPER.  255 

Tract.  At  that  place  the  ore  occupies  a  fissure  in  the 
limestone  14  feet  wide  at  the  surface,  and  traced  for  a 
quarter  of  a  mile.  For  a  depth  of  15  feet,  the  fissure 
is  filled  with  weathered  rock  or  gossan,  as  it  is  common- 
ly called,  together  with  lumps  of  sulphuret  and  carbon- 
ate of  copper.  Below  that  depth  is  clay  with  a  little 
ore  scattered  through  it.  About  a  million  and  a  half 
pounds  were  taken  from  this  fissure,  fifty  thousand  of 
which  were  sent  to  England  with  the  effect  of  bringing 
the  shippers  in  debt.  As  the  underlying  sandstone  is 
only  100  feet  from  the  surface,  and  as  it  is  probable  that 
the  ore  will  fail  there,  the  deposit  cannot  be  regarded  as 
valuable. 

In  Missouri,  the  copper  ores  also  lie  in  Silurian  rocks, 
resting  in  basins  of  the  older  rocks,  the  principal  of 
which  are  granite  and  porphyry.  The  Mine  La  Motte 
has  a  celebrity,  according  to  Mr.  Whitney,  far  beyond 
its  actual  value.  The  property  includes  24,000  acres, 
and  contains  numerous  so-called  mines.  The  most  stea- 
dily wrought  of  these  is  the  Philadelphia  mine.  Here 
the  sandstone  and  limestone  rest  on  the  granite.  The 
metalliferous  deposit  is  a  bed  lying  between  a  stratum  of 
sandstone  and  another  of  hard  crystalline  limestone. 
It  is  a  slaty  mass,  from  12  to  18  inches  wide,  contain- 
ing galena  in  flat  sheets,  and  pulverulent  ores  of  cobalt 
and  nickel.  The  copper  pyrites  occurs  in  fissures  in  the 
limestone,  disseminated  through  a  thickness  of  six  or 
eight  feet.  This  metalliferous  stratum  forms  a  lenticu- 
lar mass,  dipping  at  small  angles  in  every  direction  from 
the  centre,  and  appearing  to  be  several  hundred  feet  in 
diameter.  Mr.  Whitney  thought  the  mine  worthless. 


256  MINES  OF  COPPEK. 

He  does  not  appear  to  have  formed  a  more  favorable 
opinion  of  the  other  mines  in  the  same  State,  which  re- 
semble somewhat  the  Mine  La  Motte. 


ORES  OP  THE  ATLANTIC  STATES. 

Ores  of  copper  occur  abundantly  in  the  metamorphic 
rocks,  or  crystalline  schists  and  associated  igneous  masses 
which  extend  along  the  eastern  slope  of  the  Appalachian 
chain,  from  Vermont  to  Georgia.  Mr.  Whitney  says  in 
reference  to  them  : 

"  These  deposits,  wherever  examined,  are  found  to 
bear  a  striking  similarity  to  each  other ;  they  are  never 
found  occurring  in  well-developed  transverse  or  fissure- 
veins  ;  or  at  least,  such  has  never  come  under  my  obser- 
vation. They  all  form  masses  parallel  with  the  forma- 
tion and  possessing  all  the  characteristics  of  segregated 
veins  ;  or  if,  as  is  occasionally  the  case,  apparently  cross- 
ing the  strata  at  an  angle,  such  branches  will  be  found 
subordinate  to  segregated  masses,  and  not  exhibiting,  in 
an  unmistakable  manner,  the  phenomena  of  fissure-veins. 
The  ores  thus  occurring  are  almost  always  pyritous, 
with,  occasionally,  a  small  portion  of  the  variegated ; 
and  they  do  not  usually  appear  to  be  oxydized  to  any 
considerable  depth  from  the  surface.  Sometimes  specu- 
lar and  magnetic  oxyds  of  iron  form  the  outcrop  of  the 
vein,  and  are  replaced  to  a  greater  or  less  extent  be- 
neath by  ores  of  copper.  On  the  southwestern  side  of 
the  Appalachian  chain,  in  Tennessee,  this  decomposition 
and  the  formation  of  gossan  has,  however,  taken  place 
on  a  large  scale ;  in  other  respects  the  deposits  of  the 


MINES  OF  COPPER.  257 

ores  are  similar  to  those  of  the  eastern  slope,  except  that 
they  are  on  a  scale  of  greater  magnitude." 

MAINE. — There  are  a  few  quartz  veins,  carrying  cop- 
per pyrites,  in  this  State,  but  nothing  worthy  of  atten- 
tion. 

NEW  HAMPSHIRE. — There  are  numerous  localities  of 
copper  pyrites  in  this  State,  hut  none  of  them  have,  as 
yet,  been  worked  to  any  extent. 

Dr.  Jackson,  in  his  Report  on  the  Geology  of  New 
Hampshire,  mentions  several  towns  as  containing  ores  of 
copper,  but  condemns  the  majority  of  them  as  being  in 
too  small  quantity  for  profitable  working.  Of  two,  he 
speaks  favorably — one  in  the  town  of  Bath,  the  other  in 
Warren. 

At  "Warren,  there  is  a  remarkable  bed  of  tremolite, 
forty-eight  feet  wide,  between  walls  of  mica  slate,  which 
is  impregnated  with  copper  pyrites.  It  is  also  mixed 
with  blende,  galena,  iron  pyrites,  and  a  little  rutile. 
There  are  also  several  quartz  veins  on  the  property, 
one  of  which  carries  lead,  copper,  and  zinc,  the  predom- 
inant ore  being  argentiferous  galena.  At  the  time  of 
my  visit,  late  in  1856,  there  were  two  shafts — one  in 
the  tremolite  bed,  the  other  in  the  quartz  vein.  A  few 
tons  of  ore  had  been  taken  out,  chiefly  from  the  upper 
shaft,  or  that  sunk  in  the  quartz.  The  tremolite  is 
soft  and  easily  crushed,  and  though  it  is  not  a  regular 
vein,  yet  its  great  extent  may  enable  it  to  be  profitably 
worked.  It  is  also  quite  possible  that,  on  further  ex- 
ploration, veins  may  be  found  cutting  it,  in  which  case 
it  might  be  expected  that  they  would  be  enriched  as  they 
traversed  it.  There  are,  in  this  neighborhood,  small 
22* 


258  MINES  OF  COPPER. 

veins  which  cross  the  direction  of  the  strata.  The 
whole  region  would  justify  a  more  extensive  exploration. 
Preparations  are  now  being  made  to  work  the  mine  for 
both  lead  and  copper. 

At  Unity,  on  the  farm  of  James  Neal,  is  a  vein  of 
iron  and  copper  pyrites,  one  to  three  feet  wide,  running 
with  the  stratification,  which  has  been  traced  for  two 
thousand  feet.  Whitney  reports  the  ore  as  yielding  12 
per  cent.,  and  speaks  encouragingly  of  the  locality. 

VERMONT. — Several  localities  of  copper  pyrites  exist 
in  this  State.  At  one  of  them,  in  Corinth,  some  open- 
ings have  been  made,  from  which  ore  has  been  sent  to 
the  Revere  Copper  Works,  at  Boston.  At  Strafford, 
in  1829,  a  furnace  was  built  for  the  purpose  of  smelt- 
ing the  copper  pyrites  which  occur  there,  mixed  with 
iron,  but  the  attempt  did  not  succeed. 

MASSACHUSETTS. — A  little  pyrites  and  erubescite  has 
been  found  in  this  State,  in  veins  which  have  been 
worked  for  lead — in  Northampton  and  Southampton — 
but  not  in  sufficient  quantity  for  mining. 

CONNECTICUT. — There  is  quite  an  extensive  copper 
mine  at  Bristol,  which  was  first  worked  in  1836.  It 
is  a  contact  deposit,  at  the  junction  of  the  sandstone  of 
the  Connecticut  River  Valley  with  the  older  metamor- 
phic  rocks.  The  linear  extent  of  metalliferous  ground 
is  eleven  hundred  feet.  The  mine  is  opened,  to  the 
depth  of  forty  fathoms,  by  an  engine  shaft,  which,  at 
the  date  of  the  Report  of  Professors  Silliman  and 
Whitney,  (August,  1855,)  was  the  only  working  shaft. 
The  width  of  the  ore  ground,  from  east  to  west,  (the  depo- 
sit running  N.  E.  and  S.  W.)  is  one  hundred  and  twenty 


MINES  OF  COPPER.  259 

feet,  a  width  which  is  maintained  on  descending.  Till 
recently,  the  workings  were  confined  to  micaceous  and 
hornblende  slates,  sometimes  passing  into  gneiss,  and 
including  large  irregular  "horses"  of  granite,  which 
rock  appears  to  have  formed  segregated  masses,  lying 
rudely  parallel  with  the  bedding  of  the  schistose  rocks. 
The  strike  and  dip  of  these,  however,  is  found  through- 
out the  mine  to  be  very  irregular,  and  there  is  evidence 
in  the  confused  character  of  the  ground,  as  well  as  in 
the  slip  joints  and  polished  surfaces  of  the  rocks,  that 
motion  of  the  various  beds  upon  one  another  has  taken 
place  along  lines  of  limited  extent  and  varying  direc- 
tion. The  distribution  of  the  ores  in  the  metalliferous 
ground  now  under  consideration,  is  found  to  be  as 
irregular  as  is  the  structure  of  the  ground  itself. 
They  consist  principally  of  the  vitreous,  with  some 
variegated  ore,  and  a  comparatively  small  amount  of 
copper  pyrites.  In  general,  these  ores  are  found  occur- 
ring in  bunches  and  strings,  which,  though  preserving, 
usually,  an  approximate  parallelism  to  the  line  of  con- 
tact of  the  formations,  cannot  be  traced  continuously 
for  any  considerable  distance.  Hence  the  irregularity 
of  the  workings,  especially  in  the  upper  levels,  which 
have  been  extended  in  upon  various  bunches  of  ore, 
or  in  search  of  others  supposed  to  exist  in  certain  direc- 
tions, without  any  particular  system  or  previously  con- 
certed plan.  This  has  been  the  greatest  drawback  on 
the  prosperity  of  the  mine,  since  the  ore  ground  was 
too  wide  to  be  all  taken  down  by  the  miners,  and  the 
distribution  of  the  bunches  of  ore  in  it  was  too  irregu- 
lar to  admit  of  their  being  found  without  occasional 


260  MINES  OF  COPPER. 

expensive  excavations  in  dead  ground.  In  general, 
throughout  the  mine,  a  tendency  to  a  concentration 
of  ore  around  the  masses  of  granite  may  be  remarked, 
and  the  latter  are  not  unfrequently  well  filled  with 
strings  and  bunches  of  ore,  especially  near  their  exterior. 
"The  limits  of  the  ore  ground,  to  the  west,  or  in  the 
direction  of  the  older  rocks,  the  sandstone  being  to  the 
east  of  the  contact  line,  have  never  been  well  ascer- 
tained, and  must  be  somewhat  irregular,  as  would  be 
expected  from  the  nature  of  the  deposit."  One  of  the 
levels  -going  north  from  the  twenty  fathom  cross  cut, 
has  been  driven  along  a  regular  wall,  dipping  easterly 
at  an  angle  of  62°,  found  also  in  the  thirty  fathom 
level,  but  traceable  in  neither,  more  than  one  or  two 
hundred  feet.  Within  this  ore  ground,  the  average  dis- 
tribution of  copper  is  very  uniform.  Between  the  sand- 
stone and  this  metalliferous  belt,  lies  a  soft  talco-micace- 
ous  slate,  with  bands  and  nodules  of  harder  rock,  called 
the  "great  fluckan."  It  is  twenty-seven  feet  wide  in 
the  twenty  fathom  level,  but  gradually  increases  as  it 
descends,  till  at  fifty  fathoms  deep  it  has  attained  a  width 
of  fifty  feet.  The  authors  of  the  report  do  not  expect 
that  it  will  continue  to  widen  indefinitely,  but  regard  it 
as  a  lenticular  mass,  which  will  narrow  again.  It  con- 
tains vitreous  ore  disseminated  through  it  in  small  par- 
ticles, and  occasionally  concentrated  into  strings  and  bun- 
ches of  considerable  size.  It  has  so  far  yielded,  on  stam- 
ping arid  washing,  over  three  per  cent,  of  ore,  containing 
thirty  per  cent,  of  copper.  It  is  so  soft  as  not  to  require 
blasting,  and  when  exposed  to  air  and  moisture,  disinte- 
grates to  a  fine  clay.  Besides  these  deposits,  a  seam  of 


MINES  OF  COPPER.  261 

ore  has  been  cut  in  the  sandstone,  not  far  from  the 
flucan. 

The  mine  was  opened  in  1836,  and  though  frequently 
changing  owners  in  the  following  years,  produced  ores 
which  were  chiefly  sent  to  England.  It  was  not  till 
1847,  that  it  was  worked  to  any  considerable  extent. 
Since  then,  over  1800  tons  of  ore  have  been  taken  out 
and  sent  to  mai'ket.  It  is  a  favourite  ore  with  smelters, 
not  only  on  account  of  its  composition  but  of  the  admi- 
rably uniform  manner  in  which  it  is  dressed.  The  yield 
varies  with  the  character  of  the  ore.  I  have  made  nu- 
merous analyses  of  samples  of  cargoes  and  have  found 
none  of  lower  yield  than  18  per  cent,  of  copper,  while 
some  gave  over  50  per  cent. 

Copper  has  been  found  associated  with  the  lead  at  the 
different  localities  of  that  metal  in  this  State,  but  as  yet 
in  no  important  quantity. 

NEW  YORK. — There  are  plenty  of  mineralogical  cop- 
per localities  in  this  State,  but  none  sufficiently  impor- 
tant to  justify  mining  operations  for  that  metal  alone. 
At  the  Ulster  Lead  Mine,  copper  pyrites  has  been  found 
in  sufficient  quantity  to  render  it  worthy  of  attention 
and  separation  from  the  lead. 

PENNSYLVANIA. — The  principal  mines  in  this  State  are 
in  the  new  red  sandstone  and  will  consequently  be  no- 
ticed under  that  head.  Those  in  the  older  rocks  have 
so  far  not  been  profitable.  The  Gap  Mine,  in  Lancas- 
ter county,  is  the  oldest  of  these.  It  was  first  opened 
in  1732,  and  afterwards  taken  up  by  another  company 
which  made  large  expenditures,  but  it  has  never  paid.* 

*  Recently  it  has  been  worked  for  nickel,  and  copper  ore  of  about 
10  per  cent,  has  been  obtained  as  a  secondary  product. 


262  MINES  OF  COPPER. 

Near  Pottstown,  at  the  St.  Peter's  mine,  a  shaft  has 
been  sunk  cutting  a  vein  of  calcareous  spar,  containing 
blende  and  copper  pyrites. 

MARYLAND. — A  number  of  mines  have  been  opened  in 
this  State  and  a  few  are  still  in  operation.  In  Frede- 
rick county,  near  Liberty,  work  was  carried  on  for  some 
time,  but  finally  abandoned.  Attention  was  then  turned 
to  the  New  London  mine,  in  which  a  shaft  was  sunk  and 
levels  driven  by  Isaac  Tyson,  Jr.,  who  worked  it  for  a 
while  and  then  gave  it  up. 

Dolly  Hide  Mine,  in  the  same  neighborhood,  held  out 
for  a  time  stronger  hopes  of  success.  It  was  worked 
in  a  broad  band  of  crystalline  limestone,  which,  in  some 
places,  is  100  feet  thick,  containing  numerous  parallel 
layers  of  ore,  mixed  with  quartzose  matter,  colored 
brown  by  iron,  manganese  and  copper.  It  also  contains 
a  "black  dirt"  which  is  a  product  of  decomposition, 
having  variable  quantities  of  black  oxide  of  manganese, 
mixed  with  copper  and  iron.  The  copper  ore  when  not 
decomposed  is  chiefly  erubescite,  mixed  with  pyrites,  the 
latter  usually  scattered  in  minute  specks  through  the  for- 
mer. Some  masses  of  malachite,  chiefly  botryoidal,  of 
considerable  size,  have  been  taken  from  this  mine. 

Work  was  carried  on  irregularly,  at  intervals,  up  to 
1846,  when  it  was  leased  to  Isaac  Tyson,  Jr.,  who  car- 
ried it  on  for  several  years.  Finally  a  stock  company 
was  formed,  with  a  capital  of  $600,000.  They  worked 
it  but  a  short  time  before  they  abandoned  it.  The  de- 
posits, though  extensive,  are  too  uncertain  and  irregular 
to  justify  large  outlay  and  they  cannot  be  worked  with- 
out it.  There  is  no  likelihood  at  present  that  work 
there  will  be  resumed. 


MINES  OF  COPPER.  263 

The  yield  of  the  mine  from  1842  up  to  May  1843  is 
stated,  in  the  published  reports,  to  have  been  191,933 
pounds  of  ore  averaging  22  13-32  per  cent,  and  127  tons 
of  "black  dirt"  averaging  lOf  per  cent,  of  copper. 

In  the  neighborhood  of  Sykesville,  there  is  another 
metalliferous  belt,  occurring  among  talcose,  chloride  and 
hornblende  slates,  the  veins  being  parallel  with  the  for- 
mation. Of  these,  the  most  important  is  the  Springfield 
mine. 

Springfield  Mine. — This  mine  was  originally  opened 
by  the  Messrs.  Tyson  for  iron,  and  afterwards  worked 
for  copper.  It  is  about  a  mile  from  the  Sykesville  sta- 
tion of  the  Baltimore  and  Ohio  Railroad  and  32  miles 
from  the  city  of  Baltimore.  It  lies  among  slates  which 
are  micaceous,  talcose  or  chloritic;  the  talcose  slate 
closely  resembling  that  of  the  gold  regions  of  Virginia 
and  North  Carolina.  Gold  has  been  found  in  small 
quantity  in  the  iron  ores  of  the  neighborhood.  The 
vein  is  parallel  with  the  stratification  of  the  slates  and 
dips  with  them,  its  general  direction  being  about  north 
30°  east;  south  30°  west,  and  the  dip  nearly  vertical. 
On  the  surface  there  is  a  very  powerful  outcrop  of  a 
quartz  rock  impregnated  with  specular  and  magnetic 
oxides  of  iron  in  small  granules.  The  same  rock  makes 
its  appearance  at  the  shallow  openings  along  the  line  of 
vein,  wherever  the  surface  soil  has  been  penetrated.  A 
little  deeper,  the  oxides  of  iron  become  sufficiently  concen- 
trated to  justify  working,  and  accordingly  the  upper  levels 
have  been  stripped  for  the  use  of  the  neighboring  Elba 
furnace.  Still  lower  are  found  carbonates  and  silicates 
of  copper,  which  are  soon  replaced  by  copper  pyrites. 


264  MINES  OF  COPPER. 

The  vein  has  been  opened  by  an  engine  shaft,  which 
at  the  depth  of  66  feet,  is  cut  by  an  adit  level,  500  feet 
long,  provided  with  a  tram  road  for  the  removal  of  ore. 
At  the  time  of  my  visit,  in  February,  1857,  four  levels 
had  been  driven  and  some  stoping  done.  The  vein  thus 
exposed,  has  distinct  walls  and  selvages.  In  the  forty- 
five  fathom  level,  there  is  a  "horse"  and  a  "slide"  de- 
scending at  an  angle  of  45  degrees.  In  the  neighbor- 
hood of  these,  there  are  concentrations  of  yellow  ore 
about  four  feet  in  thickness.  A  new  shaft,  inclined  at 
the  angle  of  the  slide  has  been  made,  and  it  serves  the 
double  purpose  of  opening  the  mine  more  thoroughly, 
at  the  same  time  that  it  ventilates  it. 

This  mine  is  steadily  increasing  in  productiveness  and 
the  ores  enriching  as  they  descend.  During  the  year 
ending  April  1st,  1857,  300  tons  valued  at  $17,896.92 
were  mined  and  sent  to  market.  The  report  to  the 
stockholders  bearing  that  date,  estimates  the  present 
capabilities  of  the  mine  at  50  tons  a  month,  and  ex- 
presses the  belief  that  in  the  following  October,  it  will 
reach  125  tons  a  month,  owing  to  the  greater  amount 
of  ground  which  will  be  opened,  and  especially  to  the 
sinking  of  a  new  shaft  upon  a  vein  of  erubescite  recent- 
ly leased.  The  ore  of  the  old  vein  is  yellow  pyrites 
mixed  with  magnetic  and  specular  iron.  The  last  lot 
sent  to  the  Baltimore  market  (December  1857,)  contained 
16.03  per  cent,  of  pure  copper.  Some  nickel  and  co- 
balt are  found  in  this  mine. 

The  company  is  chartered  in  Maryland ;  the  number 
of  shares  being  100,000,  at  a  par  value  of  $5  per  share. 

Mineral  Hill  Mine  is  six  miles  northeast  of  Sykes- 


MINES  OF  COPPER.  265 

ville.  There  are  four  veins,  parallel  with  each  other, 
running  north  15°  east,  in  a  talcose  and  chloritic  slate. 
One  of  them  appears  to  be  a  fahlband  of  slate,  impreg- 
nated with  copper  pyrites  and  small  bunches  of  cobalt 
ore.  The  three  others  carry,  at  their  outcrops,  magne- 
tic and  specular  iron  with  traces  of  gold;  and,  as /  in 
Springfield,  these  gradually  give  place  to  copper  pyrites 
and  erubescite  in  the  deeper  workings. 

There  are  three  shafts,  from  which  some  ore  has  been 
taken. 

Patapsco  Mines. — This  is  owned  by  a  Philadelphia 
company.  It  was  originally  worked  in  a  heavy  bed  of 
soft  iron  ore,  containing  very  handsome  specimens  of 
fibrous  malachite  and  some  copper  pyrites.  In  the 
deeper  workings  more  copper  pyrites  was  found,  which 
was  gradually  substituted  by  cobalt.  The  mine  proved 
unprofitable. 

Bare  Hill  Mine. — The  mine  is  about  seven  miles  from 
the  city  of  Baltimore.  Although  irregularly  worked,  a 
good  deal  of  ore  has  been  taken  from  it.  These  ores 
are  pyritous,  interspersed  with  chromic,  magnetic  and 
specular  iron.  The  mine  has  been  idle  for  several 
years,  on  account  of  law-suits  respecting  its  title. 

VIRGINIA. — In  many  parts  of  this  State'  copper  is 
found;  often  native  in  sheets  lining  the  joints  of  the 
epidotic  trap  rocks  of  the  Blue  Ridge  and  in  threads 
penetrating  them ;  and  sometimes  in  the  form  of  copper 
pyrites,  erubescite,  red  oxide  of  copper,  &c. 

Manassas  Crap  Mine. — At  Manassas  Gap,  in  Fau- 
quier  county,  there  are  some  remarkable  deposits  of  cop- 
per. They  consist  chiefly  of  the  oxides  of  that  metal 
28 


266  MINES  OF  COPPER. 

embedded  in  igneous  rocks,  though  there  are  also  veins 
of  pyrites  on  the  land.  There  are  two  groups  of  veins 
imbedded  in  slates  which  have  a  nearly  vertical  dip. 
The  first  group  is  composed  of  pyrites  veins,  parallel 
with  each  other  and  with  the  formation ;  the  other  con- 
sists of  veins  containing  oxide  and  native  copper  and 
running  in  different  directions.  One  has  a  course  of 
north  30°  east,  parallel  with  the  strike  of  the  slates ; 
the  other  runs  north  70°  east.  This  cross  vein  had,  at 
the  time  of  my  first  visit,  been  cut  in  a  shallow  trench, 
dignified  by  the  name  of  a  trial  shaft.  In  that,  it  appeared 
to  be  from  10  to  12  feet  thick,  and  to  dip  at  an  angle  of 
about  62°.  At  the  time  of  my  second  visit,  work  had 
been  commenced.  An  adit  had  been  cut  in  the  side  of 
the  hill,  towards  the  veins,  with  the  intention  of  reach- 
ing them  at  a  point  where  they  were  supposed  to  inter- 
sect. In  this  adit  another  vein  had  been  cut.  A  shaft 
had  also  been  sunk  away  from  the  vein  and  a  gallery 
driven  through  dead  rock  in  the  hope  of  reaching  the 
vein  again.  These  openings  were  expensive  and  unpro- 
fitable. The  vein  would  have  been  proved  in  a  more 
economical  way  by  sinking  an  inclined  shaft  upon  it, 
and  then,  if  found  to  continue  as  it  had  begun,  more 
extensive  openings  might  have  been  made. 

The  mine  has,  I  believe,  been  abandoned.  Nothing 
could  have  been  better,  however,  than  the  surface  ore. 
I  analyzed  several  samples  of  it,  and  think  fifty  per  cent, 
to  be  a  moderate  computation  for  the  average  yield. 
The  vein-rock  itself  contained  over  two  per  cent,  of 
copper. 

In  Nelson  County  on  the  Blue  Ridge,  not  far  from 


MINES  OF  COPPER.  267 

Rock  Fish  Gap,  there  is  a  powerful  quartz  lode  contain- 
ing copper  pyrites.  It  has  never  been  worked  to  my 
knowledge. 

In  Albemarle,  at  the  Faber  lead  mine,  copper  pyrites 
also  occurs,  together  with  galena,  and  blende  or  sulphu- 
ret  of  zinc. 

The  principal  copper  region  of  the  State  is  in  the 
south-western  part,  in  the  counties  of  Carroll,  Floyd 
and  Grayson.  Here  the  slates  of  the  Blue  Ridge  ap- 
proach the  limestones  of  the  Alleghanies,  and  the  two 
ranges  of  mountains  become  blended  with  one  another, 
the  general  trend  of  both  being  north-east  and  south- 
west. The  district  is  on  the  south-western  slope  of  the 
Blue  Ridge,  about  twenty-five  miles  from  a  railroad.  The 
geological  structure  of  the  country  consists  of  slates, 
chiefly  micaceous  and  talcose,  with  some  conglomerates, 
underlaid,  according  to  Dr.  Dickerson's  report,  "  with  a 
fine-grained,  compact  hornblende  and  felspar,  analogous 
to  green  stone."  Among  these  shales  lies  a  broad  metal- 
liferous belt,  continuous,  it  is  believed,  with  the  great 
cupriferous  deposits  at  Ducktown,  Tennessee,  traceable 
by  an  outcrop  of  gossan  for  three  hundred  and  sixty 
miles.  Within  this  belt  are  found  several  distinct  beds 
of  ore,  the  outcrops  of  which  are  known  by  the  name 
of  "leads."  Dr.  Dickerson  names  five  of  these,  the 
Early,  Dalton,  Dickerson,  Toncray  and  Native  leads, 
and  says  that  he  has  heard  of  others,  but  did  not  see 
them.  These  belts  of  ore  follow,  to  some  extent,  the 
direction  of  the  bluffs  upon  which  they  occur.  "  Seams 
of  white  quartz,  interlaid  with  chloride  greenstone, 
forming  small  feeders,  often  occur,  and  invariably  carry" 


268  MINES  OF  COPPER. 

copper  ore.  At  such  points,  the  direction  of  the  lead 
is  N.  45°  E.  The  width  of  these  leads  varies  from  114 
to  32  feet.  Immediately  under  the  gossan,  a  much 
decomposed  smut  ore  occurs  in  a  greatly  altered  rock, 
so  soft  that  it  can  be  removed  by  the  pick  alone.  It  is 
a  mixture  of  red  oxide  with  sulphuret  of  copper,  and 
with  oxide  and  sulphuret  of  iron.  Below  this,  lies  an 
iron  pyrites  intimately  mixed  with  quartz,  which  is  known 
here  as  arsenical  iron,  though  there  does  not  appear  to 
be  any  arsenic  in  it.  From  the  description  in  Dr.  Dick- 
erson's  report,  it  would  seem  that  these  cupriferous 
deposits  are  in  the  form  of  lenticular  masses,  the  result 
of  decomposition  of  the  underlying  mass.  He  informs 
us  that  the  body  of  ore  is  thicker  in  the  valley,  and  that 
where  the  copper  ore  lies  high,  the  dip  of  the  so-called 
arsenical  iron  is  but  slight,  whereas  when  it  is  deeper, 
the  dip  is  steeper.  The  depth  of  this  underlying 
mundic  is  not  known,  as  jt  has  not  been  penetrated 
deeper  than  four  feet.  The  workings  for  the  examina- 
tion of  these  copper  deposits  have  been  chiefly  horizon- 
tal galleries,  driven  in  from  the  sides  of  the  hills  along 
the  course  of  the  lead,  and  cross  cuttings  made  at 
various  elevations  in  the  east  flank  of  the  mountains. 

There  are  numerous  workings  along  the  lines  of  these 
leads,  but  it  is  not  easy  to  get  information  concerning 
them.  The  oldest  of  these  is  the  Cranberry  Mine. 
"  The  property  contains  one  hundred  acres,  and  extends 
half  a  mile  on  the  lead.  Two  shafts  had  been  sunk  on 
the  south  end  of  the  lead,  below  the  summit  of  the 
bluffs,  which  proved  the  lode  upwards  of  600  feet. 
From  the  side  of  the  hill  a  horizontal  gallery  was  driven, 


MINES  OF  COPPER.  269 

on  a  course  of  45°  E.  of  N.,  and  extended  upwards  of 
400  feet,  giving  an  average  width  of  seventeen  feet  of 
copper  ore.  The  south  wall  is  well  defined,  being  composed 
of  a  talco-micaceous  slate,  containing  now  and  then  small 
patches  of  garnets  of  beautiful  form  and  color.  Nume- 
rous small  vugs  occur  in  this  gallery,  many  of  which 
are  filled  with  the  finest  crystalline  forms  of  ore."  The 
ore  is  taken  out  of  variable  richness.  Dr.  Dickerson 
speaks  of  having  seen  masses  of  oxide  weighing  more 
than  a  ton,  and  containing  sixty  per  cent,  of  metallic 
copper. 

There  are  twelve  or  fourteen  openings  in  this  great 
metalliferous  belt,  worked  mostly  by  companies  organized 
on  the  copartnership  system. 

The  Cranberry  Mine  is  one  of  the  oldest  of  these 
openings.  Its  property  contains  a  hundred  acres,  and 
extends  half  a  mile  upon  the  lead.  At  the  date  of  Dr. 
Dickerson's  report,  two  shafts  had  been  sunk  below  the 
summit  of  the  bluffs.  From  the  side  of  the  hill  a  hori- 
zontal gallery  had  been  driven  for  over  400  feet, 
cutting  copper  ore  of  an  average  width  of  seventeen 
feet.  A  hundred  feet  from  the  opening,  streaks  of 
flucan  were  discovered,  and  near  them  a  large  deposit  of 
red  oxide  of  copper.  The  south  wall  is  well  defined, 
consisting  of  talco-micaceous  slate  containing  fine  gar- 
nets. In  this  gallery  are  numerous  vugs,  many  of 
which  are  filled  with  fine  crystals.  The  ore  bed  is  com- 
posed of  two  distinct  layers,  the  upper  containing  the 
best  ore.  The  average  percentage  of  the  ores  taken 
from  this  mine  is  set  down  at  26'43. 

The  Wild  Cat  Mine  adjoins  the  Cranberry  on  the 
.23* 


270  MINES  OF  COPPER. 

West,  its  openings  being  made  upon  both  the  Early  and 
the  Dalton  leads.  The  property  contains  three  hundred 
and  fifty  acres,  and  is  seventeen  miles  from  Mack's 
Meadows,  a  station  on  the  Virginia  and  Tennessee  rail- 
road, with  which  it  is  connected  by  a  good  turnpike 
road.  It  extends  half  a  mile  on  either  lead.  Mining 
was  commenced  here  in  February  1855,  by  an  open 
cut,  from  which  a  gallery  was  driven  into  the  hill.  The 
geological  features  of  this  mine  are  the  same  as  those  of 
the  last  described.  The  veins  in  the  valley  dip  more 
perpendicularly,  and  are  considered  richer.  The  north 
wall  is  well  defined,  and  filled  with  small  garnets. 

The  Ann  Phipps  Mine  is  next  to  the  West,  owning 
a  property  of  a  hundred  and  forty  miles,  extending  a 
mile  upon  the  Early  lead.  Work  was  commenced  late 
in  March,  1855.  According  to  Mr.  Richardson's  letter 
in  the  London  Mining  Journal,  the  channel  of  mine- 
ralized ground  on  this  estate  is  one  hundred  feet  thick, 
containing  a  champion  lode  eight  feet  thick,  on  a  foot 
wall  of  mica  slate,  having  an  underlie  of  55°  S.  E., 
and  a  range,  as  traced  by  out-croppings,  of  50°  N.  of 
E.,  which  will  probably  change  to  35°  in  the  deep  work- 
ings. The  country  and  hanging  wall  are  composed  of 
mica  and  clay  slate  with  garnets.  The  matrix  is  quartz 
and  iron  pyrites.  In  the  higher  levels,  there  is  much 
gossan  and  decomposed  slate.  There  is  also  a  strong 
flucan  on  the  foot  wall.  On  the  surface  there  is  much 
bright  gossan,  impregnated  with  grey  and  black  ore, 
the  branches  of  the  lode.  At  thirty-five  feet  below, 
these  concentrate,  and  a  solid  mundick  is  reached,  filled 
with  yellow  and  grey  ore.  Of  the  yield  of  this  mine,  I 
have  no  statistics. 


MINES  OF  COPPER.  271 

The  Dalton  Mine  is  three-fourths  of  a  mile  south-east 
of  the  Ann  Phipps.  The  shaft,  according  to  Mr. 
Richardson,  is  sunk  in  a  ravine,  penetrating  twenty  feet 
into  the  lode,  and  twelve  into  solid  mundick.  As  usual, 
upon  the  surface,  there  is  gossan.  The  quartz  vein, 
twelve  feet  thick,  contains  eight  per  cent,  of  yellow 
copper. 

Of  the  other  mines  in  this  region,  I  have  no  reliable 
information. 

NORTH  CAROLINA. — There  are  a  number  of  copper 
mines  in  this  State,  none  of  which  have,  as  yet,  pro- 
duced a  great  deal  of  ore,  though  many  of  them  look 
very  promising.  Copper  is  certainly  very  widely  dis- 
tributed through  the  state.  In  the  north-western 
corner,  at  Ore  Knob,  in  Ashe  County,  a  mine  has  been 
worked  for  several  years,  and  has  produced  some  excellent 
yellow  ore.  This  appears  to  be  in  the  same  range  with 
the  mines  in  south-western  Virginia.  Following  the 
same  line  down  along  the  Eastern  slope  of  the  Unaka, 
Smoky,  and  other  mountains  dividing  Tennessee  from 
North  Carolina,  there  are  numerous  deposits  of  copper. 
On  my  visit  to  that  region,  in  December,  1855,  there 
was  much  excitement  in  regard  to  ores  of  this  metal, 
and  numerous  openings  had  been  made,  but  too  imper- 
fect to  enable  any  one  to  arrive  at  any  definite  conclu- 
sions in  reference  to  the  matter.  In  the  south-western 
part  of  the  State,  on  both  sides  of  the  Blue  Ridge, 
among  the  micaceous  and  talcose  slates,  there  were  evi- 
dences of  the  presence  of  copper,  and  at  numerous 
points  upon  the  creeks  in  Macon  and  Jackson  counties, 
yellow  and  grey  ore  of  fine  quality  had  been  taken  out 


272  MINES  OF  COPPER. 

in  small  quantities.  It  is  my  impression  that  this  region 
will,  on  proper  exploration,  be  found  to  contain  not  a 
little  metallic  wealth. 

An  important  region  for  gold,  silver,  copper  and  lead, 
exists  in  the  centre  of  the  State,  occupying  the  counties 
of  Gruilford,  Cabarras,  Mecklenburgh  and  Davidson. 

North  Carolina  Copper  Company. — The  mine  worked 
by  this  company  is  about  nine  miles  from  Greensboro'  in 
Guilford  County.  It  was  formerly  worked  for  gold,  and 
known  as  the  Fentress  or  Stith's  Mine.  In  1852,  it 
was  purchased  by  a  New  York  Company,  and  by  them 
it  has  been  worked  for  copper  only.  The  cupriferous 
deposit  has  a  direction  parallel  with  that  of  the  slates 
in  which  it  is  enclosed,  about  N.  30°  E. ;  its  dip,  which, 
at  the  surface,  is  only  15°,  gradually  increases ;  and  is, 
at  seventy  feet  in  perpendicular  depth,  about  45°.  The 
ore  is  almost  solely  pyritous  copper,  associated  with 
some  sulphuret  of  iron.  It  is  said,  on  good  authority, 
that  there  is  a  large  quantity  of  ore  exposed,  but  the 
work  has  thus  far  been  conducted  with  an  entire  want  of 
judgment,  the  only  aim  seeming  to  be  to  raise  as  much  ore 
immediately,  without  regard  to  the  future  of  the  mine. 
At  the  time  of  the  publication  of  Whitney's  metallic 
wealth  of  the  United  States,  to  which  I  am  indebted  for 
the  above  information,  it  was  reported  by  the  parties  in- 
terested, that  they  were  raising  one  hundred  tons  of 
twenty-five  per  cent,  ore  monthly.  I  have  been  able  to 
get  no  further  information,  except  that  the  company  in- 
tend erecting  smelting  furnaces  for  separating  the  me- 
tallic from  the  earthy  parts  of  the  ore. 

In  most  of  the  old  gold  mines,  copper  pyrites  is  found, 


MINES  OF  COPPER.  273 

and  much  of  this  ore  has  accumulated  from  the  gold 
workings.  Some  of  them  are  now  worked  conjointly 
for  both  metals,  and  the  opinion  of  those  who  have  had 
opportunities  of  judging,  is,  that  they  will  prove  valu- 
able for  copper.*  At  the  McCullock  Mine,  in  Guilford 
County,  the  copper  ore  is  found  in  a  layer  of  quartz, 
overlying  iron  pyrites,  the  gold  being  underneath  both. 

TENNESSEE. — Following  the  range  of  mountains  be- 
tween this  State  and  North  Carolina,  from  the  Virginia 
frontier,  the  explorer  finds  copper  in  different  localities. 
Imperfect  explorations  have  been  made  at  various  points 
on  this  range,  without  any  satisfactory  result,  so  far  as 
I  have  been  able  to  learn,  except  in  the  extreme  south- 
eastern portion  of  the  State.  There,  in  Polk  County, 
on  the  Ocoee  River,  is  a  very  remarkable  deposit  of 
copper,  which  has  attracted  no  little  attention,  and  sent 
a  good  quantity  of  ore  to  market. 

The  region  in  which  these  ores  occur  is  an  old  Indian 
province,  known  by  the  name  of  Ducktown.  It  is  an 
elevated  basin  or  trough,  lying  between  the  Unaka  and 
the  Blue  Ridge,  about  a  thousand  feet  above  the  level  of 
the  valley  of  East  Tennessee.  The  country  is  cut  up  into 
knolls  and  ridges  of  tolerably  uniform  height,  and  the  dis- 
trict is  traversed  by  the  Ocoee  River,  a  tributary  of  the 

*  In  a  private  letter  to  the  author,  Dr.  F.  A.  Genth  says  of  the 
mines  of  this  region :  "  As  a  general  thing,  all  true  veins,  »'.  e.,  such  as 
intersect  the  strata,  and  are  not  merely  metalliferous  strata  of  the 
formation,  apparently  will  turn  to  copper  veins  at  a  greater  depth. 
They  contain  generally  less  gold  near  the  surface,  rarely  averaging 
more  than  fifty  per  cent,  per  bushel,  but  at  and  below  the  water  level, 
the  indications  of  copper  appear,  and  become  stronger  with  every  foot 
sinking. 


274  MINES  OF  COPPER. 

Tennessee.  The  geological  formation  is  made  up  of  mica- 
ceous and  talcose  slates,  with  some  hornblende,  dipping 
at  a  high  angle  towards  the  south-east,  and  running  N. 
20°  E.  These  are  crossed  by  quartz  veins,  but  the 
great  metalliferous  beds  are  parallel  with  one  another 
and  the  strike  of  the  strata.  At  the  time  of  Whitney's 
visit,  there  were  but  two  of  these  known,  and  upon  only 
one  of  them  had  any  important  openings  been  made, 
but  Prof.  Safford,  the  Geologist  of  the  State,  writing  in 
1856,  speaks  of  seven  or  eight  distinct  veins,  the  course 
of  six  of  which,  he  figures  on  his  map. 

The  appearance  of  these  veins  is  remarkably  uniform. 
The  surface  is  marked  by  a  heavy  outcrop  of  gossan, 
which  is  particularly  conspicuous  on  the  knolls  and 
ridges,  where  it  is  often  found  in  great  blocks  scattered 
over  a  width  of  fifty  or  a  hundred  feet.*  Beneath  this 
gossan  is  found  a  mass  of  black  cupriferous  ore,  which, 
like  the  gossan,  has  resulted  from  a  decomposition  of  a 
mixture  of  the  sulphurets  of  copper  and  iron.  The 
depth  at  which  this  smut  ore  occurs  varies,  being  greater 
on  the  hills  than  in  the  valleys.  In  the  former  locality, 
it  is  found  80  or  90  feet  below  the  surface,  in  the  latter 
it  is  reached  at  25  or  30.  It  corresponds  very  closely 
as  might  be  expected,  with  the  water  level.  It  is  a  mix- 
ture of  the  red  oxide  of  copper  with  the  sulphuret  and 
some  silicious  matter,  varying  in  its  yield  of  pure  copper 

*  J.  P.  Lesley,  in  his  report  on  the  Hiwassee  mine,  suggests  that 
these  veins  may  have  been  originally  deposited  as  sedimentary  rocks 
and  subsequently  altered  by  heat.  Their  parallelism  is  accounted  for 
by  the  folded  condition  of  the  stratification,  the  upper  curves  having 
been  removed  by  denudation. 


MINES  OF  COPPER.  275 

from  15  to  60  per  cent.,  20  per  cent,  being  about  the 
average.  Below  this  is  found  the  unaltered  mineral  of 
the  vein,  a  very  hard  rock  consisting  of  a  pinkish  iron 
pyrites  mixed  with  quartz  and  containing  some  yellow 
copper  ore. 

The  thickness  of  the  veins  containing  these  deposits  is 
often  enormous.  At  the  Hiwassee  mine,  the  body  of 
black  ore  was  said  to  be  45  feet  wide,  and  at  the  Eure- 
ka, Mr.  Staunton,  the  secretary,  informs  me  there  is 
a  mass  of  solid  ore  52  feet  in  width.  At  other  points  it 
thins  out,  and  finally  disappears.  The  thickness  is 
equally  variable.  At  some  places  it  is  accumulated  in 
conical  masses  to  the  amount  of  several  hundred  tons. 
Whitney  estimated  the  average  width  of  the  deposits  at 
10  feet  and  the  thickness  at  2. 

One  of  the  most  remarkable  features  about  these  mines 
is  the  great  economy  with  which  they  may  be  worked. 
Shafts  can  be  sunk  through  the  gossan  without  being 
timbered,  and  the  ore  can  be  taken  out  with  picks  and 
shovels,  while  the  veins  are  so  wide  that  several  men 
can  work  abreast  in  the  levels.  The  ridges  too  are  so 
posited,  as  to  afford  great  facilities  for  driving  levels 
across  the  veins. 

The  permanent  value  of  these  mines  will  of  course 
depend  upon  the  character  of  the  veins  below  the  oxide, 
for,  however  rich  and  abundant  that  may  be,  it  is  evi- 
dent that  it  must  soon  be  worked  out.  The  average  of 
the  rock  is  altogether  too  poor  to  admit  of  its  being  pro- 
fitably worked,  and  unless  the  copper  pyrites  should  be 
found  to  concentrate  in  rich  bunches,  these  mines  must 
be  abandoned  as  soon  as  all  the  black  ore  is  removed. 


276  MINES  OF  COPPER. 

Impressed  with  this  truth,  the  miners  have  prosecuted 
certain  openings  with  a  view  of  determining  this  point. 
The  Hiwassee  mine,  which  has  nearly  if  not  quite  ex- 
hausted its  black  ore,  has  cut  several  bunches  of  yellow 
ore  in  its  lower  levels,  which  have  excited  the  hopes  of 
its  owners.  According  to  the  best  information  I  have 
been  able  to  obtain,  however,  I  cannot  regard  this  ques- 
tion as  decisively  settled. 

The  history  of  mining  enterprise  in  this  region,  as 
given  by  Professor  Saiford,  in  his  report  to  the  Legisla- 
ture, is  briefly  as  follows.  The  first  discovery  of  copper 
was  made  by  a  Mr.  Lemmons,  in  1843.  He  was 
washing  for  gold  at  the  present  site  of  the  Hiwassee 
mine,  and  found  red  oxide  of  copper.  Shortly  after 
this,  a  company  discovered  the  black  oxide,  but  consid- 
ering it  worthless,  they  did  not  include  it  in  a  package 
of  the  minerals  and  rocks  of  the  vicinity  which  they  sent 
to  New  York  for  analysis.  Receiving  necessarily  an 
unfavorable  report,  they  suspended  operations  for  the 
time  being.  In  1847,  being  informed  by  a  German  of 
the  value  of  the  black  oxyd,  they  made  a  shipment  of 
about-  14  tons,  averaging  25.3  per  cent.  About  the 
same  time  a  furnace  was  erected  to  make  iron  out  of  the 
gossan,  but  the  metal  produced  was  red  short  and  the 
enterprise  was  abandoned.  Still,  certain  facts  were  ascer- 
tained, such  as  the  green  flame  of  the  furnace,  and  the 
cupreous  hue  of  the  iron  after  it  had  been  heated  and 
plunged  into  water.  In  1849,  Mr.  John  Caldwell  came 
into  the  neighborhood,  and  mainly  through  his  indefati- 
gable energy,  public  attention  was  attracted  to  this 
region.  In  1850,  the  Hiwassee  and  Cocheco  companies 


MINES  OF  COPPER.  277 

were  incorporated.  The  following  year,  the  Tennessee 
Mining  Company  broke  ground,  and  after  that  the  tract 
was  gradually  taken  up  by  the  fourteen  companies  who 
now  occupy  it. 

The  Hiwassee  Mine  commenced  regular  operations 
in  May,  1852,  on  a  vein  45  feet  wide,  included  in  walls 
of  mica  slate.  Other  veins  are  spoken  of  as  parallel. 
The  main  lode  corresponds  in  strike  and  dip  with  the 
strata,  having  a  direction  of  north  20  east  and  a  dip  of 
80°  to  the  southeast.  The  average  depth  of  the  black 
ore  was  estimated  by  Lesley  at  five  feet,  and  its  width 
at  30,  the  whole  amount  being  calculated  at  7200  tons. 
The  mine  has  sent  to  market  about  6000  tons  and  has  ex- 
hausted its  smut  ore.  Efforts  are  now  making  to  strike 
the  yellow  sulphuret  and  the  prospects  are  encouraging, 
several  deposits  of  greater  or  less  magnitude  having 
been  reported.  As  in  all  other  mines,  the  gangue  be- 
low the  point  of  decomposition  is  a  hard  quartzose  rock 
containing  much  iron  pyrites  and  some  yellow  copper. 
The  adit  of  this  mine  is  920  feet  long,  and  serves  as  a 
draining  gallery  for  the  mine.  The  entire  length  of  the 
shafts  in  September,  1856,  is  stated  by  Professor  Safford 
at  641  feet,  and  the  extent  of  the  galleries  at  2784  feet. 

The  capital  stock  is  $240,000,  divided  into  60,000 
shares. 

The  Eureka  Mine  is  worked  in  a  metalliferous  belt 
300  feet  wide.  This  has  been  traced  by  an  outcrop  of 
gossan  for  2250  feet,  in  the  direction  of  the  strike  of 
the  strata.  The  mine  has  been  opened  by  a  main  shaft 
105  feet  deep,  from  which  galleries  have  been  driven 
across  the  belt.  Several  beds  of  ore  have  been  cut,  and 
24 


278  MINES  OF  COPPER. 

from  their  direction  they  are  expected  to  coalesce  below. 
One  of  these  presents  a  mass  of  ore  52  feet  thick. 
There  are  now  in  view,  according  to  the  report,  thou- 
sands of  tons  of  ore. 

The  economy  of  freight  is  a  matter  of  so  much  impor- 
tance that  the  company  has  erected  smelting  furnaces  at 
the  mine.  Wood  is  the  fuel  employed  and  the  furnaces 
are  on  the  reverberatory  plan.  The  cost  of  smelting 
for  a  year  is  estimated  at  $21,272,  the  products  of  the 
furnaces  for  the  same  time  being  worth  $67,742. 

The  capital  stock  of  the  company  is  $500,000  divided 
into  10,000  shares.  The  proceeds  of  the  year  ending 
March  21st,  1857,  were  485  tons  of  ore  averaging  23 
per  cent.,  260  tons  of  regulus  averaging  50  per  cent, 
and  3766  pounds  of  copper. 

The  Isabella  Mine  has  stopped  on  account  of  pecuni- 
ary difficulties.  Its  entire  product  has  been  estimated 
at  4000  tons  averaging  16  per  cent.  Professor  Safford 
states  the  production  for  September,  1855,  at  120  tons 
containing  29  per  cent,  of  copper. 

The  Polk  County  Mine  is  engaged  in  a  suit  about  the 
title  and  has  stopped  in  consequence.  In  September, 
1855,  according  to  the  authority  just  quoted,  it  sent  to 
market  108  tons  of  ore  of  29J  per  cent.  Its  entire  pro- 
duction has  been  stated  to  be  about  2500  tons  of  ore 
averaging  20  per  cent. 

The  Mary's  Mine  has  sent  away  about  1500  tons 
averaging  28  per  cent.  Its  monthy  product  is  about 
40  tons. 

The  London  Mine  has  very  rich  ores,  averaging 
45  per  cent.  Its  monthly  product  is  stated  at  40  tons. 


MINES  OF  COPPER.  279 

The  Cocheco  Mine  has  been  till  recently  in  litigation. 
At  present  it  promises  well,  the  openings  having  exposed 
a  large  amount  of  marketable  ore. 

GEORGIA. — There  are  several  localities  in  this  state 
which  are  thought  to  promise  well  for  copper  but  I  have 
been  able  to  obtain  no  definite  information  concerning 
them. 

The  Canton  Mine  is  chiefly  valuable  for  its  silver- 
lead,  but  has  produced  also  a  remarkable  ore  of  copper, 
called  by  Professor  Shepard,  Harrisite.  It  is  a  pseudo- 
morph  of  galena  and  is  very  rich  in  copper,  containing, 
according  to  Genth's  analysis,  nearly  78  per  cent,  of  that 
metal.  The  vein,  according  to  Professor  Shepard's  re- 
port, is  a  quartzy  mica-slate,  breaking  into  small  blocks, 
and  containing  galena,  copper  and  iron  pyrites,  and  re- 
ceiving a  dropper  vein  carrying  gray  ore.  The  capital 
stock  of  the  company  is  $960,000.  They  have  already 
taken  out  large  quantities  of  ore,  chiefly  silver- lead. 
They  propose  erecting  a  furnace  at  their  mine,  for  the 
separation  of  the  silver  and  lead. 

COPPER   ORES   IN   THE   NEW   RED    SANDSTONE. 

The  new  red  sandstone  is  a  belt  of  rocks  which  follows 
the  flanks  of  the  Appalachian  chain,  attaining  its  great- 
est development  in  Connecticut  and  New  Jersey,  where 
it  is  thirty  miles  wide.  Throughout  this  range  there 
are  numerous  irruptions  of  trap  and  in  the  vicinity  of 
the  junction  of  these  two  rocks  the  copper  ores  occur. 

NEW  ENGLAND. — In  Massachusetts  copper  ores  have 
been  found,  but  have  never  been  worked  to  any  extent. 
In  Connecticut,  in  the  eastern  end  of  the  town  of  Gran- 


280  MINES  OF  COPPER. 

by,  are  the  Simsbury  copper  mines  which  were  worked 
in  the  early  part  of  the  last  century.  The  company 
was  chartered  in  1709,  and  appears  to  have  been  the 
first  incorporated  mining  company  in  the  country.  Ac- 
cording to  Professor  Shepard,  the  ore  occurs  in  beds, 
nodules  and  strings,  in  a  fine-grained,  yellowish  gray 
sandstone.  The  principal  ore  is  vitreous  copper.  A 
good  deal  of  ore  was  taken  out  at  different  times,  but 
about  the  middle  of  the  last  century,  the  mines  were 
abandoned  and  lay  idle  for  forty  years,  after  which  they 
were  purchased  by  the  State  and  used  as  a  prison  for 
sixty  years.  In  1830  they  again  passed  into  the  hands 
of  a  company,  were  worked  for  a  few  years  and  finally 
abandoned. 

NEW  JERSEY. — Quite  a  number  of  openings  have  been 
made  in  this  State,  and  the  carbonates,  oxides  and  sul- 
phurets  of  copper  have  been  found  in  considerable  quan- 
tities, but  not  at  any  point  in  regular  veins.  For  the  follow- 
ing history  we  depend  chiefly  upon  Whitney's  abstract, 
and  upon  Rogers'  report  on  the  geology  of  New  Jersey. 

From  1748  to  1750,  several  lumps  of  native  copper, 
weighing  in  all  over  200  pounds,  were  ploughed  up  in  a 
field  belonging  to  Philip  French,  near  New  Brunswick. 
A  company  was  formed,  and  in  1751,  a  shaft  was  sunk 
on  a  spot  "where  a  neighbor,  passing  in  the  dark,  had 
observed  a  flame  rising  from  the  ground,  nearly  as  large 
as  the  body  of  a  man."  After  a  time,  a  sheet  of  copper 
"  somewhat  thicker  than  gold-leaf,"  was  found  between 
walls  of  loose  sandstone.  Lumps  also  varying  from  5  to 
30  pounds  in  weight  were  taken  out.  After  following 
the  vein  for  30  feet,  the  company  abandoned  their  enter- 


MINES  OF  COPPER.  281 

prise  on  account  of  the  difficulty  of  removing  the  water. 
Meanwhile  they  had  stamped  out  and  sent  to  England 
several  tons  of  copper.  It  is  said  that  sheets  of  copper 
"of  the  thickness  of  two  pennies  and  three  feet  square," 
were  taken  from  between  the  rock,  within  four  feet  of 
the  surface. 

The  ScJiuyler  Mine,  near  Belleville,  in  Essex  county, 
on  the  left  bank  of  the  Passaic,  seven  miles  from  Jersey 
City,  was  discovered  by  Arent  Schuyler,  about  1719, 
The  ore  was  abundant  near  the  surface  and  easily  mined. 
It  was  worked  by  the  discoverer  and  his  son,  and  before 
the  year  1731,  1386  tons  of  ore  had  been  taken  out  and 
sent  to  England.  Li  1761,  the  mine  was  leased  to  a 
company,  which  worked  it  for  four  years,  and  abandoned 
it  after  their  engine  house  had  been  set  on  fire  by  a  dis- 
charged workman.  Several  companies  have  spent  a  good 
deal  of  money  on  it  since  the  Revolution,  but  it  has 
never  been  profitably  worked. 

According  to  Professor  Rogers'  report,  the  principal 
body  of  the  ore  is  embedded  in  a  stratum  of  sandstone 
20  or  30  feet  thick,  dipping  about  12°  from  the  horizon, 
rather  by  steps  than  regularly.  It  has  been  worked 
212  feet  below  the  surface  and  150  feet  horizontally 
from  the  shafts.  The  ores  are  principally  sulphurets 
and  carbonates  of  copper  which  are  diffused  through  the 
indurated  sandstone.  There  is  no  trap  exposed  on  the 
surface  anywhere  in  the  immediate  neighborhood. 

At  the  Falls  of  Passaic,  near  Paterson,  traces  of  cop- 
per have  been  found,  and  fruitless  excavations  have  been 
made,  in  search  of  a  regular  vein.  In  the  neighborhood 
of  New  Brunswick,  "  prior  to  the  revolutionary  war,  an 
24* 


282  MINES  OF  COPPER. 

extensive  and  costly  attempt  was  made  to  establish  a 
mine,  but  without  success."  There  are  blue  and  green 
carbonates  in  the  shale,  and  occasionally  metallic  copper 
is  found  in  the  shape  of  a  thin  plate  injected  into  the 
body  of  the  rock,  which  is  hardened  and  changed  from 
red  to  gray  in  the  immediate  vicinity  of  the  metal. 

At  the  Franklin  Mine  near  Griggstown,  in  Somerset 
county,  the  ore  is  found  in  a  shale  altered  by  its  proxi- 
mity to  trap.  It  is  usually  diffused,  but  sometimes  oc- 
curs in  narrow  short  strings,  mixed  with  crystalline 
minerals.  It  has  been  worked  to  the  depth  of  100  feet 
and  drained  by  a  long  adit.  Much  money  has  been  ex- 
pended here  without  any  return. 

The  Bridgewater  Mine,  at  the  base  of  the  trap  ridge, 
north  of  Somerville,  is  another  of  these  ruinous  invest- 
ments. As  in  all  the  others,  the  first  openings  were 
very  promising.  Out  of  the  altered  shale  were  taken 
quantities  of  red  oxide  of  copper  and  native  copper. 
Of  the  latter,  two  masses  weighing  1900  pounds,  are 
said  to  have  been  found  in  1754.  A  smelting  furnace 
was  erected  by  some  Germans  about  the  middle  of  the 
last  century,  but  soon  abandoned.  In  1824,  the  mine 
was  again  opened  and  worked,  and  as  before,  money 
was  lost. 

The  Flemington  Mine  was  the  only  one  actually 
worked  at  the  date  of  Professor  Rogers'  report,  (1836.) 
He  describes  the  ore  as  consisting  of  gray  sulphuret 
and  carbonate  of  copper,  intimately  blended  and  incor- 
porated with  semi-indurated  and  altered  sandstone,  parts 
of  the  mass  having  the  appearance  of  a  conglomerate  of 
recemented  fragments.  The  metalliferous  belt,  some- 
times twenty  or  thirty  feet  wide,  preserves  a  north  and 


MINES  OF  COPPER.  283 

south  direction  for  several  hundred  feet.  The  ores  are 
mixed  gray  sulphurets  and  carbonates.  They  are  of 
very  good  quality.  I  find,  by  reference  to  my  record 
of  analyses  for  1849  and  1850,  that  commercial  samples 
of  lots  sent  to  Baltimore  varied  from  28  to  50  per  cent. 
An  attempt  was  made  at  one  time  to  smelt  the  ores  on 
the  spot,  but  resulted  in  loss.  Some  of  the  slag,  con- 
taining 8  per  cent,  of  copper,  was  sold  in  Baltimore. 
The  mine  was  finally  abandoned,  the  metallic  deposit 
being  too  uncertain  for  profitable  working.  I  visited 
the  mine  in  1855,  but  was  not  able  to  go  down  into  the 
shafts,  owing  to  the  presence  of  water,  and  am  conse- 
quently unable,  from  personal  observations,  to  add  any- 
thing to  what  has  already  been  stated  on  the  authority 
of  Whitney  and  Rogers. 

"It  would  seem  as  if  these  failures  might  have  been 
sufficient  to  warn  capitalists  from  wasting  any  more 
money  in  these  mines.  The  State  Geologist,  in  his  re- 
port, remarks  that  there  are  no  true  veins  in  this  for- 
mation, and  warns  against  further  expenditures,  unless 
made  with  the  greatest  caution. 

"  Notwithstanding  all  this,  New  Jersey  had,  in  1846 
and  1847,  a  little  copper  fever  as  well  as  Lake  Superior. 
In  1847,  there  were  six  mining  companies  organized  in 
this  district,  with  69,500  shares,  and  their  market  value 
exceeded  $1,000,000.  The  Raritan  mine,  three  miles 
southwest  of  New  Brunswick,  was  purchased  at  a  high 
price,  and  large  expenditures  were  made  under  the  ad- 
vice of  Dr.  C.  T.  Jackson  and  J.  H.  Blake,  Esq. 
The  Passaic  Mining  company  erected  a  steam  engine 
and  expended  a  large  sum  of  money,  near  the  old  Schuy- 
ler  mine.  The  Nechanic  mine,  near  Flemington,  which 


284  MINES  OF  COPPER. 

had  been  worked  before  the  Revolution,  was  re-opened 
at  a  considerable  expense.  The  Washington  mine,  near 
the  old  Bridgewater  mine,  at  Somerville,  was  another  of 
these  unfortunate  concerns,  in  which  the  future  profits 
per  acre  were  calculated  to  the  fraction  of  a  dollar. 

"All  these  mines  were  abandoned,  after  heavy  expen- 
ditures, with  almost  total  loss  of  the  whole  amount  invest- 
ed; and  it  is  to  be  hoped  that  no  more  money  will  be 
sunk  in  them."* 

CUPRIFEROUS   VEINS    AT   THE   JUNCTION   OF   GNEISS   AND 
NEW   RED   SANDSTONE. 

In  Montgomery  and  Chester  counties,  Pennsylvania, 
there  is  a  metalliferous  zone  running  east  and  west 
across  the  Schuylkill  river,  occupying  a  belt  of  country 
six  or  seven  miles  long,  in  the  vicinity  of  Perkiomen  and 
Pickering  creeks,  not  far  from  the  junction  of  the  gneiss 
with  the  new  red  sandstone.  Within  this  space  are 
some  ten  or  twelve  lodes,  some  of  which  are  confined 
entirely  or  chiefly  to  the  gneiss,  while  others  traverse 
the  red  shale.  The  former  bear  lead  as  their  principal 
metal,  while  in  the  latter  copper  predominates.  The 
gneiss  is  much  decomposed  to  a  very  considerable  depth, 
and  is  intersected  by  numerous  dykes  of  granite,  green- 
stone, trap  and  other  igneous  rocks,  which  sometimes 
cut  the  strata  vertically  and  sometimes  are  parallel  with 
the  planes  of  the  enclosing  rock. 

The  Perkiomen  Consolidated  Mining  Company  was 

organized  in  1851,  by  the  consolidation  of  the  Ecton  and 

Perkiomen  mines,  both  of  which  were  on  the  same  lode, 

their  engine  shafts  being  about  1800  feet  apart.     In 

*  Whitney.     Op.  tit. 


MINES  OF  COPPER.  285 

April,  1852,  the  report  of  the  manager,  C.  M.  Wheat- 
ley,  states  that  the  engine  shaft  in  the  Perkiomen  mine 
was  passing  the  50  fathom  level,  and  that  the  lode  at 
that  depth,  was  from  four  to  nine  feet  wide,  made  up  of 
quartz,  gossan  and  sulphate  of  baryta,  with  green  car- 
bonate of  copper  and  copper  pyrites  in  place.  It  had 
decidedly  improved  from  the  40  fathom  level  down.  At 
the  Ecton  mine,  the  54  fathom  level  was  driving  from 
the  engine  shaft  west,  in  a  lode  varying  from  two  to  five 
feet  in  width,  with  good  copper  pyrites  but  not  worth 
stoping.  In  May,  1853,  the  Perkiomen's  shaft  is  re- 
ported to  be  62  and  the  Ecton  shaft  66  fathoms  deep, 
but  the  lode  poor  in  ore  in  both  mines.  From  August, 
1851  to  April,  1852,  524  tons  of  ore,  varying  from  7 
to  23  per  cent,  of  copper,  were  sold  by  this  company, 
for  $30,573.  In  1853,  it  is  stated  that  the  sales  for  the 
year  were  142  tons  of  ore  for  $9,989. 

Since  September  1853,  the  mine  has  not  been  raising 
ores. 

Ores  have  also  been  found  in  New  Mexico  and  on  the 
Gadsden  purchase.  The  Arizona  mine,  in  the  latter 
tract,  has  sent  to  Baltimore  and  to  Swansea  very  rich 
ores  containing  some  fine  crystallizations  of  the  red 
oxide,  but  I  have  been  unable  to  obtain  satisfactory 
information  concerning  the  mine. 

Copper  ores  are  also  said  to  abound  about  the  head 
waters  of  the  Gila  river,  where  several  mines  are  report- 
ed to  have  been  worked.  The  most  celebrated  is  that 
of  Santa  Rita  del  Cobre,  the  ores  of  which  are  red  oxyd 
imbedded  in  a  red  feldspathic  rock.  A  Frenchman  who 
worked  it  from  1828  to  1835,  is  said  to  have  made  half 
a  million  of  dollars  from  it. 


CHAPTER  V. 

COPPER    SMELTING. 

THE  object  of  smelting  the  ores  of  copper  is,  of  course, 
to  obtain  the  metal  in  a  state  sufficiently  pure  for  the 
purposes  of  commerce.  The  degree  of  purity  or  fine- 
ness required  depends  upon  the  use  to  which  the  copper 
is  to  be  put.  For  certain  alloys  it  is  not  absolutely  ne- 
cessary that  it  should  be  perfectly  malleable,  while  for 
tubes,  wire,  or  sheets,  it  must  be  thoroughly  refined. — 
The  processes  for  obtaining  it  vary  greatly  in  different 
countries,  and  depend  entirely  upon  the  nature  of  the 
ores  and  the  character  of  the  fuel  which  is  employed. 
The  simplest  of  these  is  that  practiced  upon  the  native 
copper  of  Lake  Superior. 

SMELTING   LAKE  COPPER. 

For  the  purpose  of  obtaining  pure  malleable  copper 
from  the  masses,  stamp  and  barrel-work  sent  down  from 
the  mines  of  Lake  Superior,  it  is  only  necessary  to  sepa- 
rate the  earthy  matter  which  still  adheres  to  the  metal, 
and  then  to  deprive  the  copper  of  the  oxygen  it  has 
absorbed  while  in  the  liquid  state.  The  furnaces  do  not 
differ  materially  from  those  to  be  presently  described, 
when  we  come  to  speak  of  the  English  method  of  smelt- 
ing. They  are  reverberatories  of  an  ordinary  construc- 
tion. 


COPPER  SMELTING.  287 

Sometimes  the  whole  process  is  conducted  in  a  single 
furnace.  In  this  case  the  ore  is  charged  into  the  fur- 
nace, mixed  with  a  flux  adapted  to  the  nature  of  the 
earthy  matter  under  treatment.  The  heat  is  kept  up 
till  the  whole  is  fused,  when  the  copper,  owing  to  its  greater 
specific  gravity,  sinks,  while  the  liquid  earthy  matter  or 
slag  floats  upon  its  surface.  This  slag  is  now  drawn  off" 
the  face  of  the  copper  by  means  of  rabbles,  and  the 
metallic  bath  is  exposed.  During  the  fusion,  the  copper 
has  of  course  absorbed  oxygen,  which,  if  allowed  to  re- 
main, would  render  the  metal,  to  a  great  extent,  fragile. 
The  surface  is,  therefore,  covered  with  charcoal,  and 
rods  of  green  wood  are  plunged  into  the  metallic  bath, 
in  order  to  reduce  the  oxide.  The  refining  being  com- 
pleted, the  metal  is  laded  out,  and  poured  into  moulds. 
At  other  times,  two  furnaces  are  used,  and  in  that 
case  the  metal  is  first  obtained  in  the  form  of  pigs,  which 
are  afterwards  refined.  The  slags  taken  from  these  fur- 
naces are  very  rich  in  copper,  containing  numerous  shots 
and  flakes  of  copper  diffused  through  them.  They  are 
therefore  worked  over  again  with  an  additional  quan- 
tity of  flux,  in  order  to  obtain  as  much  as  possible  of 
this  retained  metal.  Still  the  slag  is  found  to  contain 
too  much  copper  to  be  thrown  away.  In  order  to  obtain 
this,  the  slags  are  passed  through  a  small  cupola  furnace. 
The  resulting  slag  may  be  considered  clean,  but  there 
has  been  an  unavoidable  waste  of  copper,  which  has  vola- 
tilized at  the  high  heat  of  the  cupola  and  passed  out  of 
the  chimney. 

The  establishments  at  which  the  lake  copper  is  work- 
ed, are  at  Detroit,  Cleveland,  and  Pittsburgh. 


288  COPPER  SMELTING. 

ENGLISH    PROCESS    OP    COPPER   SMELTING. 

By  far  the  largest  amount  of  copper  produced  at  any 
one  locality  for  smelting,  is  obtained  from  the  copper 
works  of  Swansea,  in  South  Wales.  Indeed  the  product 
of  those  great  furnaces  is  estimated  at  more  than  one 
half  of  the  entire  world.  The  process  there  adopted  is 
a  tedious  and  intricate  one,  but  appears,  on  the  whole, 
the  best  adapted  to  a  general  smelting  establishment. 
It  is  undoubtedly  susceptible  of  improvement,  as  it  has 
been  recently  estimated  that  not  less  than  ten  or  twelve 
per  cent,  of  the  entire  yield  of  copper  in  Great  Britain 
and  Ireland  is  lost  in  the  smelting. 

The  average  yield  of  the  ores  of  British  and  Irish 
mines  sold  in  Swansea,  may  be  estimated  at  6.7  per  cent. 
The  actual  amount  obtained  from  the  furnaces  does  not 
amount  to  more  than  6  per  cent.,  so  that  0.7  per  cent, 
of  the  ore,  or  nearly  12  per  cent,  of  the  copper  contain- 
ed in  it  has  disappeared.  This  statement,  however, 
probably  does  not  accurately  represent  the  actual  loss. 
Some  of  this  has  soaked  into  the  bottoms,  some  has  been 
carried  into  the  culvert,  where  it  is  not  beyond  the  reach 
of  the  smelter.  Another  portion,  however,  has  gone 
away  in  the  slag,  and  as  it  cannot  be  profitably  extract- 
ed, it  is  irrecoverably  lost. 

To  meet  this  loss,  the  smelters  have  adopted  a  series 
of  rules,  which  transfer  it  from  their  shoulders  to  those 
of  the  miners.  In  the  first  place,  the  smelter's  ton  con- 
sists of  21  hundred  weights,  or  2852  pounds,  so  that  five 
per  cent,  is  gained  here.  Again,  the  ore  is  all  bought 
by  the  dry  essay.  This,  as  has  already  been  said,  is 
never  accurate,  the  loss  being  greater  in  the  crucible 


COPPER  SMELTING.  289 

than  in  the  furnaces.  This  difference  between  the  assay- 
room  and  the  works,  increases  in  an  inverse  proportion 
to  the  richness  of  the  ore.  Thus,  in  an  ore  ranging 
from  three  to  six  per  cent.,  the  crucible  loses  at  least 
fifteen  per  cent,  of  the  copper  more  than  the  furnaces, 
while  in  one  containing  twenty-five  per  cent.,  the  differ- 
ence would  not  be  more  than  five  per  cent.  Besides 
these,  there  are  minor  charges  put  upon  the  ore.  Much 
dissatifaction  has  for  some  time  existed  on  the  part  of 
the  miners  at  these  arrangements,  but  experience  has 
long  since  proved  that  they  would  lose  far  more  if  they  un- 
dertook to  smelt  for  themselves.  Independently  of  the 
superior  advantages  which  the  smelters  at  Swansea  enjoy, 
in  the  proximity  of  coal,  and  the  facilities  for  transpor- 
tation, they  can  work  cheaper  than  the  miners,  because 
there  is  always  a  decided  loss  attending  the  attempt  to 
work  one  class  of  ores  alone. 

The  rationale  of  the  process  adopted  at  Swansea  will 
be  better  understood  after  an  acquaintance  with  the 
character  of  the  ores  smelted  there.  These  are  divided 
into  five  classes : 

First  Class. — These  consist  almost  entirely  of  copper 
pyrites,  containing  a  large  proportion  of  iron  in  the 
state  of  sulphuret,  and  mixed  with  much  mundick  or  iron 
pyrites.  They  contain  little  or  no  carbonate  or  oxide 
of  copper.  The  earthy  and  silicious  ingredients  are  in 
large  proportion,  so  that  the  amount  of  copper  ranges 
from  three  to  sixteen  per  cent. 

Second  Glass. — Resembles  the  first,  with  the  difference 
that  they  are  richer,  containing  from  fifteen  to  twenty- 
five  per  cent,  of  copper. 
25 


290  COPPER  SMELTING. 

Third  Class. — Copper  pyrites  containing  but  little 
iron  pyrites  or  other  substance  likely  to  impoverish  the 
metal  produced,  and  having  a  large  proportion  of  oxidiz- 
ed ores  of  copper. 

Fourth  Class. — The  basis  of  these  ores  is  usually 
/  quartz.  They  contain  from  twenty  to  thirty  per  cent, 
of  copper  in  the  form  of  oxide  and  carbonate,  mixed 
with  some  sulphuret. 

Fifth  Class. — Rich  ores  from  Chili  or  South  Austra- 
lia, containing  often  eighty  per  cent,  of  copper,  in  the 
form  usually  of  carbonate  or  red  oxide.  The  gangues 
are  commonly  silicious. 

It  is  evident  that  the  object  to  be  attained  is  the  libe- 
ration of  the  copper,  not  only  from  the  earthy  matters 
in  which  its  ores  are  imbedded,  but  also  from  the  sulphur, 
oxygen  and  iron  with  which  it  is  chemically  combined. 
These  results  are  arrived  at  by  a  series  of  calcinations 
and  smeltings,  which  vary  with  the  ore  under  treatment. 
M.  Le  Play  has  classified  these  various  processes  under 
ten  heads,  and  we  shall  follow  his  order  in  describing 
them. 

I.  Calcination  of  the  ores  of  the  first  and  second  class 
to  expel  sulphur. 

II.  Melting  the  calcined  with  raw  or  unburnt  ore,  to 
separate  the  earthy  matters  and  to  obtain  a  matt  or  coarse 
metal. 

III.  Calcination  of  the  coarse  metal  still  further  to 
expel  sulphur. 

IV.  Fusion  of  the  calcined  metal  with  rich  ores  of 
the  fourth  class,   to  get  rid  of  iron  and  obtain  white 
metal. 


COPPER  SMELTING.  291 

V.  Melting  for  blue  metal,  or  fusion  of  the  calcined 
coarse  metal  with  roasted  ore,  moderately  rich  in  cop- 
per. 

VI.  Re-melting  of  rich  slags  to  recover  the  copper 
contained  in  them. 

VII.  Roasting  for  white  metal,  or  production  of  white 
metal  of  extra  quality.     This  operation  sometimes  in- 
cludes the  roasting  of  the  blue  metal  obtained  in  process 
V. 

VIII.  Roasting  for  regulus. 

IX.  Preparation   of  crude  copper,  by  roasting  and 
melting  white  metal,  regulus,  &c. 

X.  Refining  and  production  of  tough  malleable  copper. 
The  furnaces  in  which  these  operations  are  performed 

are  all  of  the  reverberatory  form,  but  differ  in  their  di- 
mensions and  the  slope  of  the  roof.  In  well-conducted 
establishments,  they  are  all  connected  with  an  under- 
ground culvert  in  which  volatilized  copper  is  arrested  and 
recovered. 

The  calciner,  in  which  the  first  operation  is  more  spa- 
cious than  the  others.  The  hearth,  or  laboratory  of  the 
furnace,  is  elliptical  in  form,  truncated  at  the  extremi- 
ties of  its  long  axis,  and  having,  between  the  openings 
through  which  the  charge  is  removed,  angular  projec- 
tions towards  the  centre  of  the  bed.  It  is  sixteen  feet 
long,  and  thirteen  and  a  half  wide.  It  is  formed  of 
fire-bricks  set  on  edge,  and  firmly  bedded  in  refractory 
fire  clay.  Each  of  its  sides  is  provided  with  two  work- 
ing doors,  through  which  the  various  operations  of  stir- 
ring and  raking  down  the  ore  are  performed.  Imme- 
diately within  each  of  these  doors,  is  an  opening  through 


COPPER  SMELTING. 


,    — 


PLAN    OF    CALCINING   FURNACE. 

R,  Sole  of  furnace.  F,  Fireplace,  a  a,  Side  or  working  doors,  e  e  e  e.  Openings 
communicating  with  the  vault,  d,  Special  air-hole,  which  can  be  opened  or  closed 
at  pleasure.  H  H,  Flues. 


which  the  calcined  charge  is  raked  down  into  the  arched 
chambers  beneath.  While  the  calcination  is  going  on, 
these  are  kept  closed  by  iron  plates  which  are  removed 
at  the  close  of  the  operation,  to  admit  of  the  removal  of 
the  roasted  ores.  The  arch,  which  has  a  mean  height  of 
two  feet  above  the  sole,  descends  rapidly  from  the  fire- 
place to  the  flue-holes,  at  the  other  end  of  the  long  axis, 
through  which  the  gases  escape  into  the  chimney.  A 
current  of  cold  air  is  admitted  by  an  opening  near  the 
fire-place,  which  can  be  closed  at  pleasure.  In  some 


COPPER  SMELTING. 


293 


forms  of  the  furnace,  a  channel  is  made  in  the  fire- 
bridge, through  which  passes  a  current  of  air  having 
the  advantage  of  being  heated,  and  consequently  more 
active. 


Fia.  10. 


CALCINING   FURNACE.       SECTION. 

A  B,  Level  of  sole.    C,  Vault  into  which  the  calcined  ore  is  raked.     H,  Flue.     E, 
Sole  of  furnace,    a  a,  Working  doors.    S  S,  Hoppers. 

The  arch  of  the  furnace  supports  two  large  hoppers 
of  sheet  iron,  provided  with  sliding  doors  at  the  bottom. 
Into  these  the  ore  is  placed,  and  allowed  to  drop  into 
the  furnace  on  the  removal  of  the  slides.  Outside,  the 
furnace  is  bound  together  by  strong  iron  bands,  arranged 
both  perpendicularly  and  horizontally. 

The  coal  used  in  the  Swansea  works  is  anthracite,  the 
combustion  of  which  presents  many  difficulties  to  be 
overcome  by  the  smelter.  It  ignites  slowly  and  imper- 
fectly, and  on  being  heated  flies  into  powder,  which 
either  falls  through  the  bars,  or  accumulates  and  chokes 
25* 


294  COPPER  SMELTING. 

the  draught.  Besides,  it  produces  a  fusible  ash,  which, 
at  a  high  temperature,  runs  into  a  glassy  slag,  that  not 
only  chokes  the  draught,  but  rapidly  corrodes  the  bars 
of  the  grate. 

To  obviate  these  difficulties,  the  smelter  has  recourse 
to  very  simple  methods.  He  places  his  grate-bars  wide 
apart,  and  throws  pieces  of  scoria  loosely  upon  them 
till  he  has  formed  a  layer  about  a  foot  thick.  Upon 
these  the  fire  is  made,  and  the  ashes  accumulate.  They 
all  fuse  together  to  a  spongy  silicious  mass,  everywhere 
traversed  by  a  great  number  of  apertures.  As  this 
matter  accumulates,  the  fireman,  from  time  to  time,  de- 
taches the  lower  portion  and  allows  it  to  fall  into  the 
hearth.  Thus  he  has  a  grate  formed  of  slag,  containing 
interstices  too  small  to  permit  the  fragments  to  fall 
through,  and  yet  sufficient  for  a  draught.  The  gases 
arising  from  this  combustion  consist  chiefly  of  carbonic 
oxide,  which  passes  over  the  fire-bridge  into  the  body  of 
the  furnace.  Here  it  meets  the  stream  of  air  introduced 
through  the  openings  already  mentioned,  and  others 
which  are  left  in  the  iron-plates  closing  the  lateral  open- 
ings. Thus  the  whole  cavity  of  the  furnace  is  always 
filled  with  flame,  caused  by  the  carbonic  oxide  burning 
as  it  comes  in  contact  with  the  atmosphere.  The  mine- 
rals spread  over  the  sole,  are,  therefore,  exposed  to  a 
current  of  air,  above  which  is  a  parallel  sheet  of  car- 
bonic oxide,  burning  on  its  under  surface  where  it  comes 
in  contact  with  the  oxidizing  stratum,  and  so  affording 
sufficient  heat  to  conduct  the  entire  operation. 

The  charge,  which  consists  of  three  or  three  and  a 
half  tons,  is  introduced  without  any  intermission  in  the 
action  of  the  furnace,  by  simply  withdrawing  the  slides 


COPPER  SMELTING.  295 

at  the  bottom  of  the  hoppers.  As  soon  as  it  has  been 
let  down,  it  is  spread  evenly  over  the  furnace  bottom  by 
means  of  long  iron  rakes  introduced  through  the  work- 
ing doors,  which  are  then  immediately  closed.  The  fire 
is  then  replenished  with  the  proper  amount  of  coal,  the 
cinders  loosened,  and  the  heat  gradually  raised.  The 
object  of  this  process  is  to  get  rid  of  a  certain  amount 
of  sulphur ;  but,  in  order  to  accomplish  this,  great  care 
is  necessary.  If  the  heat  be  pushed  too  rapidly  at  first 
the  ore  will  agglutinate,  thus  shielding  a  portion  of  it 
from  the  influence  of  the  air,  and  impairing  the  result, 
besides  obstructing  the  walls  and  sole  of  the  furnace  by 
collections  of  fused  sulphuret.  After  six  or  eight  hours, 
the  heat  may  be  raised,  as  then  much  of  the  sulphur  has 
been  expelled,  and  the  disposition  to  agglutinate  is  less. 
At  first,  watery  vapor  passes  off,  and  then  sulphurous 
acid.  To  facilitjite_Jjia  action  by  exposing  fresh  sur- 
faces to  the  action  of  the  oxidizing  agents,  the  charge  is 
stirred  every  two  hours,  by  a  long  iron  tool  called  a 
rabble,  till  no  more  volatile  products  pass  off,  or  until 
the  peculiar  stage  of  oxidation  demanded  by  the  con- 
dition of  the  ore,  and  exigencies  of  the  other  furnaces  is  i 
attained.  Towards  the  close  of  the  operation,  the  heat  is 
pushed,  and  the  furnace  raised  to  its  highest  temperature. 
The  iron-plates  covering  the  openings  behind  the  doors 
are  then  removed,  and  the  calcined  ore  raked  down  into 
the  chambers  below.  This  is  a  trying  operation  to  the 
•workman,  as  the  unpleasant  effects  of  the  heat  are  in- 
creased by  the  fumes  of  sulphurous  and  sulphuric,  and 
often  of  arsenious  acid,  which  arise  from  this  glowing 
mass.  These  are  caused  by  the  presentation  of  a  greater 
surface  to  the  action  of  fresh  air,  which  evolves  still 


296 


COPPER  SMELTING. 


0.374 

22.710 

22.442 

1.001 

0.608 


more  gas  than  was  expelled  in  the  furnace.  Imme- 
diately after  the  removal  of  one  charge,  another  is  intro- 
duced. The  time  occupied  by  this  operation  is  usually 
twelve  hours,  though  it  sometimes  reaches  twenty-four. 

Little  or  no  loss  in  weight  is  sustained  in  calcination, 
as  the  sulphur  expelled  is  substituted  by  oxygen  ab- 
sorbed. M.  Le  Play,  who  carefully  examined  these  ope- 
rations, has  given  the  following  tables  of  the  ore  before 
and  after  calcination,  which  show  the  chemical  changes 
it  has  undergone. 

BEFORE  CALCINATION. 
Oxide  of  copper,  isolated  or  combined,    .... 

Copper  pyrites,         ........ 

Iron  pyrites,  bisulphide  of  iron,         ..... 

Various  sulphides,    ........ 

Oxide  of  iron,     ....         ..... 

Other  oxides,      ......... 

Quartz  and  silica,     ........  34.428 

Earthy  bases,     .........     1.871 

Water  and  carbonic  acid  in  combination,          .         .         .     0.491 
Oxygen  consumed,    ........  15.806 

...........  100.000 

AFTER  CALCINATION. 
Oxide  of  copper,       ........     5.401 

Copper  pyrites,         .         .         ......  11.228 

Bisulphide  of  iron,  .         .         .         .         .         .         .         .  11.226 

Other  sulphides,       .........  600 

Ferric  oxide,    .........  11.718 

Other  oxides,    ..........  608 

Sulphuric  acid  in  combination,          .....     1.108 

Quartz  and  silica,     ........  34.408 

Earthy  bases,  ..        ........     1.874 

Gaseous  products,  /  Sulphurous  acid,      .         .         .         .21.338 

I  Water  and  carbonic  acid,         .         .     0.491 


100.000 


COPPER  SMELTING.  297 

In  these  tables,  no  account  is  taken  of  the  arsenical  pro- 
ducts which  are  scarcely  ever  absent.  The  matters  escap- 
ing from  a  calcining  furnace  may  be  said  to  consist  of 

Vapor  of  water, 

Sulphurous  and  sulphuric  acids, 

Arsenious  acid,  and  arsenical  vapors, 

Fluoride  of  silicium,  and  other  volatile  compounds  of 
fluorine,  - 

Solid  matter,  mechanically  conveyed  by  the  draught 
into  the  flue, 

Carbonic  acid,  &c. 

The  water  comes  from  the  oxidation  of  the  hydrogen 
of  the  coal,  as  well  as  from  the  moisture  contained  in 
the  ore.  Coming  in  contact  with  the  sulphurous  acid, 
it  gives  rise  to  sulphuric  acid.  The  fluoride  of  silicium 
results  from  the  action  of  the  silicious  gangue  upon  the 
fluor  spar  (fluoride  of  calcium)  contained  in  the  ore. 
The  rest  of  the  volatile  products  need  no  particular 
explanation. 

All  the  vapors  pass  off  into  the  atmosphere,  and  from 
their  enormous  quantity,  exert  the  most  unfavorable 
influence  upon  vegetation.  Not  a  blade  of  grass  can 
grow  for  a  considerable  distance  around  Swansea,  in  the 
direction  of  the  prevailing  winds,  so  that  the  smelters 
are  obliged  to  incur  the  expense  of  buying  up  large 
tracts  which  they  do  not  want  and  cannot  use.  The 
curse  of  absolute  sterility  rests  upon  the  environs  of  the 
furnaces,  and  this  will  surprise  no  one  who  has  ascer- 
tained, by  a  simple  calculation,  that  the  amount  of  sul- 
phurous and  sulphuric  acids  given  off  from  the  numerous 
chimneys  of  Swansea,  cannot  be  less  than  ninety  thou- 


298  COPPER  SMELTING. 

sand  or  one  hundred  thousand  tons.  The  loss  has  not 
been  confined  to  the  agriculture  of  the  district  alone ; 
the  smelters  have  also  suffered.  The  sulphur,  volatil- 
ized, is  worth  .£120,000  a  year,  and  if  estimated  as 
common  commercial  sulphuric  acid,  to  which  condition 
it  could  be  easily  reduced,  it  would  afford  an  annual 
revenue  of  £450,000. 

Some  attempts  have  been  made  to  get  rid  of  the  poi- 
sonous fumes.  At  first  it  was  thought  that,  by  erecting 
very  tall  chimneys,  these  vapors  would  be  mingled  with 
a  large  bulk  of  air,  and  so  neutralized  by  the  ammonia, 
as  to  be  rendered  comparatively  inert.  Again,  it  was 
attempted  to  build  vitriol  chambers  in  connection  with 
the  shaft.  Another  plan  was  to  conduct  the  volatile 
matters  through  long  galleries  or  troughs  holding  water, 
and  covered  by  perforated  slabs  of  stone  placed  horizon- 
tally, over  which  a  stream  of  water  was  kept  constantly 
flowing.  In  these  troughs,  they  meet  the  percolating 
water  which  absorbs  much  of  the  sulphuric  acid.  The 
difficulty,  however,  was  that  the  presence  of  so  much 
liquid  interfered  with  the  draught,  so  that  the  measure 
was  abandoned. 

Second  Operation.  The  ore,  being  cooled,  is  wheeled 
in  barrows  to  the  next  furnace,  in  which  the  first  smelt- 
ing is  performed.  The  object  is  to  separate  as  much  as 
possible  of  the  iron  and  all  of  the  earthy  matters.  The 
temperature  employed  is  higher,  and  the  charge  much 
less,  than  in  the  preceding  operation.  The  iron  enters 
into  combination  with  the  silica,  forming  a  fusible  slag, 
and  though  there  is  usually  enough  silica  to  combine 
with  the  iron,  it  is  customary  to  add  a  slag  rich  in  cop- 


COPPER  SMELTING.  299 

per,  from  one  of  the  other  furnaces,  in  order  to  effect  a 
more  thorough  combination.  As  the  slags  from  this 
process  are  usually  rejected,  it  is  important  to  have  them 
as  clean  as  possible.  There  is  always,  however,  a  por- 
tion of  it  which  contains  a  little  copper  mechanically 
mixed  with  the  scoriae,  which  is  sent  back  to  the  furnace 
to  be  worked  over.  The  residue,  which  is  called  "  clean 
slag,"  is  thrown  away,  or  employed  to  make  roads,  to 
raise  the  grade  of  the  yards,  to  lay  the  foundations  of 
other  furnaces,  &c.  In  spite  of  all  the  uses  which  have 
been  found  for  it,  however,  it  becomes  quite  a  serious 
matter  at  Swansea  to  determine  how  it  shall  be  dis- 
posed of.  Beginning  near  the  furnaces,  and  gradually 
going  further  and  further,  the  smelters  have  surrounded 
their  works  -with  hills  of  refuse.  Of  late,  it  has  been 
the  practice  of  some  of  the  establishments  to  form  the 
rejected  slag  into  tiles,  slabs,  and  bricks,  suitable  for 
building. 

There  is  always  a  little  loss  of  metal  in  this  slag, 
which  is  generally  estimated  at  from  four  to  five-tenths  of 
one  per  cent,  of  the  entire  metal  contained  in  the  ore. 
It  can,  however,  with  care  be  reduced  to  two  or  three- 
tenths,  though  this  is  by  no  means  common. 

The  furnace  in  which  this  operation  is  performed,  is 
not  more  than  one-third  the  size  of  the  calciner.  In 
most  furnaces  it  is  charged  through  the  top,  and  conse- 
quently needs  no  side-door ;  but  in  some,  it  is  provided 
with  one  side-door,  through  which  the  charge  is  intro- 
duced. At  the  opposite  side  of  the  furnace  is  an  open- 
ing, called  the  tap-hole,  through  which  the  molten  metal 
is  allowed  to  flow  out.  The  bottom  is  made  of  a  refrac- 
tory sand,  which  is  agglutinated  by  heat,  before  the 


300 


COPPER  SMELTING. 
FIG.  11. 


SMELTING  FURNACE  PLAN. 

A  Sole  of  furnace.  B,  Depression  for  the  accumulation  of  metal.  F,  Fire-place. 
MMMM,  Sand  moulds  for  slag.  V,  Water  tank.  W,  Winch  for  raising  from  fur- 
nace. 

a  a  Outlet  for  melted  metal,    d  Working  door  for  draining  off  slag. 

charge  is  introduced.  It  is  depressed  towards  the  tap- 
hole,  to  allow  the  molten  metal  to  flow  out  readily,  and 
so  worked  as  to  form  a  sort  of  basin  immediately  within 
that  opening.  In  front  of  the  furnace  is  a  door,  through 
which  the  scoriae  are  raked  out,  the  ore  stirred,  and  the 
various  repairs  of  the  furnace  bottom  accomplished. 
Immediately  below  this  door,  outside  of  the  furnace,  are 
sand-moulds  to  receive  the  fluid  slag,  which  is  withdrawn 
from  the  surface  of  the  metal.  Near  the  tap-hole  is 
usually  a  tank  of  water,  with  an  iron  pot  on  the  bot- 


COPPER  SMELTING. 


301 


torn,  which  may  be  lifted  out  by  a  crane.  In  this,  the 
metal  tapped  out  from  the  furnace,  becomes  granulated. 
The  fire-place  is  larger  in  proportion  to  the  size  of  the 
furnace  than  in  the  calciner.  Its  dimensions  are  about 
four  feet  by  three  and  a  half,  while  that  of  the  bed  of 
the  furnace  are  only  about  eleven  by  seven.  The  fire 
is  made  as  usual,  but  at  Swansea  about  one-third  of  bitu- 
minous coal  is  added  to  the  anthracite  for  the  purpose 
of  obtaining  a  hotter  fire  than  the  calciner  can  furnish, 
the  greater  heat  being  needed  for  the  fusion  of  the  sub- 
stances. 

FIG.  12. 


SMELTING    FURNACE    SECTION. 

H.  Hopper  for  charging.     M,  The  other  letters  hare  the  same  reference  as  in  the 
preceding  figure. 

The  charge  usually  consists  of  seventeen  or  eighteen 
hundred  weight  of  calcined   and  two  or  three  hundred 
weight  of  crude  ore  of  the  third  class.     To  these  are 
26 


302  COPPER   SMELTING. 

added  three  and  a  half  hundred  weight  of  slag  contain- 
ing copper,  and  obtained  from  operations  IV.,  V.,  and 
VII.  These  subserve  the  double  purpose  of  rendering 
the  slag  more  fusible,  and  of  giving  up  to  the  metal  the 
copper  they  contain.  The  ore  and  the  finer  portion  of 
the  flux  are  introduced  through  the  hopper,  and  the 
coarser  portions  of  the  latter  are  thrown  in  at  the  door. 
This  is  quickly  spread  upon  the  bed  of  the  furnace,  and 
the  larger  pieces  of  slag  are  then  thrown  in.  The 
charge  having  been  introduced,  the  door  is  closed  and 
luted,  and  the  tap-hole  blocked  up  with  sand  and  scoriae. 
The  fire  is  then  pushed,  and  the  charge  remains  undis- 
turbed for  about  three  hours  and  a  half,  except  for  the 
necessary  examination  of  the  process.  Fresh  fuel  is 
thrown  on  at  the  end  of  an  hour  and  a  quarter,  or 
thereabouts.  This  furnace  consumes  about  thirty-four 
and  a  half  hundred  weight  of  coal  in  the  twelve  hours. 

The  first  effect  of  the  heat  becomes  manifest  in  about 
half  an  hour  after  the  spreading  of  the  ore  on  the 
hearth  of  the  furnace.  The  slag  then  begins  to  melt 
and  form  little  pools  or  channels  full  of  liquids.  Soon 
after,  the  fluid  mattter  begins  to  extend  over  the  hearth, 
in  consequence  of  the  formation  of  a  fusible  silicate  by 
the  iron  and  silicic  acid  present  in  the  ores  and  slags. 
As  the  quantity  of  liquid  matter  increases,  it  is  agitated 
by  the  evolution  of  sulphurous  acid  gas,  formed  at  the 
expense  of  the  sulphuret  of  iron,  which  becomes  oxidized, 
and  combines  with  the  silica.  Fluor  spar  greatly  assists 
these  actions,  its  fluorine  entering  into  combination  with 
the  silica,  and  forming  a  volatile  compound  which  carries 
off  arsenic.  At  the  end  of  the  three  hours  and  a  half,  the 


COPPER  SMELTING.  303 

charge  is  nearly  melted.  The  furnace  man  now  opens  the 
door,  and  by  means  of  a  long  rabble,  stirs  it,  bringing 
the  unmelted  portions  more  directly  in  contact  with  the 
fused  mass,  and  causing  it  to  fuse.  The  heat  is  now 
increased,  and  kept  high  till  the  fusion  is  completed. 
The  molten  bath  is  now  divisible  into  two  layers,  the 
upper  containing  the  earthy,  and  the  lower  the  metallic 
contents  of  the  ore.  The  former  of  these  is  now  re- 
moved through  the  front  door  by  a  process  of  rabbling. 
In  some  instances,  a  new  charge  is  now  thrown  in  on 
top  of  the  bath,  to  increase  the  metallic  yield  of  the  fur- 
nace, but  usually  the  "  coarse  metal,"  as  it  is  called,  is 
tapped  out,  and  a  fresh  charge  introduced  afterwards. 

The  separation  of  the  slag  from  the  metal  is  never 
perfect.  A  little  copper  is  always  found  in  the  lower 
layer  of  liquid.  Most  of  this  subsides  to  the  bottom  of 
the  central  pig  of  slag,  which  is  kept  liquid  by  the  con- 
tinual addition  of  fresh  molten  matter  from  the  furnace. 
What  is  not  arrested  by  this  plate  slag,  passes  over 
to  those  on  either  side  of  it.  The  quantity  of  metal 
contained  in  these  slags,  varies  with  many  circumstan- 
ces. Thus,  if  the  matt  be  very  poor,  and  the  slag  of 
nearly  the  same  degree  of  fluidity  with  the  metallic 
bath  on  which  it  rests,  there  will  be  more  metal  mechan- 
ically mixed  with  it  than  if  the  matt  were  heavier,  or 
the  difference  in  the  fluidity  of  these  two  superimposed 
baths  greater.  The  cleanliness  of  a  slag  depends  upon 
a  proper  adjustment  of  all  these  particulars,  and  re- 
quires no  little  skill  and  experience  for  its  accomplish- 
ment. 

The  slag,  having  cooled  sufficiently,  is  wheeled  out  to 
the  heap,  where  it  is  broken  up  and  examined.  Those 


304  COPPER  SMELTING. 

fragments  which  contain  metal,  are  sent  back  for  re- 
smelting  with  the  next  charge.  It  is  no  easy  matter  to 
attain  the  exact  composition  of  a  charge  to  produce  the 
best  effect.  The  most  important  point  is  to  make  such 
a  fusible  mixture  that  the  matt  may  subside  by  reason 
of  its  greater  specific  gravity,  and  separate  exactly  from 
the  slag.  This  is  greatly  assisted  by  the  oxide  of  iron 
in  the  scoriae  of  the  fourth  operation,  which  are,  as  we 
have  already  said,  added  to  the  charge.  Much,  also, 
depends  upon  the  admixture  of  earthy  matters  in  the 
ores.  The  best  results  are  obtained  when  these  are  so 
proportioned  as  to  form  a  highly  crystalline  slag.  In 
practice,  it  is  customary  to  make  several  trials  with  dif- 
ferent combinations  of  the  ores  in  the  yard,  until  such 
a  mixture  is  hit  upon.  After  that,  nothing  is  required 
but  toTollow  the  routine"  thus  established.  When  the 
variety  of  ores  is  large,  the  simplest  plan  is  to  mix  the 
poor  and  rich  ores  in  such  proportions  as  to  obtain  the 
average  per  centage  of  the  matt,  when  the  various  earths 
in  combination  with  the  different  ores  flux  one  another, 
and  give  the  desired  result.  It  is,  however,  evidently 
not  always  possible  to  do  this.  In  cases  of  difficulty, 
the  usual  practice  is  to  make  a  full  quantitative  analysis 
of  the  ores,  and  to  construct  a  proper  mixture  by  the 
light  thus  afforded.  It  may  happen  that  this  reveals 
the  fact  that  the  ores  alone  will  not  produce  a  fusible 
mixture.  In  this  case,  fluor  spar  or  limestone  is  added ; 
but  it  is  desirable  to  avoid  this,  if  possible,  as,  if  too  great 
a  quantity  of  slag  be  made,  a  corresponding  loss  of  cop- 
per will  be  sustained  by  the  mechanical  retention  of 
minute  particles  of  metal. 

The  man  who  superintends  this  operation  is  called 


COPPER  SMELTING.  305 

the  roaster-man,  and  much  depends  upon  his  skill  and 
knowledge  of  the  working  of  the  furnace.  He  deter- 
mines the  heat  by  inspecting  the  interior  of  the  furnace, 
through  a  hole  in  the  tile  which  closes  the  door,  to  ascer- 
tain if  it  has  reached  the  proper  degree  of  incandescence. 
If  it  be  not  hot  enough,  the  fire  is  examined  to  deter- 
mine whether  the  fuel  be  excessive  or  insufficient,  and 
whether  the  draught  be  strong  enough,  and  the  defect, 
when  ascertained,  is  immediately  remedied.  It  is  impor- 
tant to  regulate  the  quantity  of  air  passing  through  the 
furnace.  If  this  be  too  great — that  is,  more  than  suffi- 
cient for  the  combustion — it  shortens  the  flame  and  di- 
minishes the  heat. 

Four  hours  are  required  to  work  off  each  charge,  so 
that  this  about  balances  the  calciner,  which,  though 
much  larger,  requires  much  longer  time  to  do  its  work. 
The  heat  must  be  kept  up  during  these  four  hours,  in 
order  to  keep  the  contents  of  the  furnace  in  perfect 
fusion.  If  this  is  not  done,  the  ore  may  adhere  to  the 
bottom.  At  the  end  of  the  heat,  the  slag  is  skimmed 
off,  as  already  described,  and  the  furnace  tapped.  The 
entire  amount  of  slag  is  not,  however,  removed,  as,  in 
that  event,  the  matt  would  be  covered  with  a  layer  of 
oxide  of  copper,  which  would  diminish  its  fluidity,  and 
render  it  difficult  to  flow  out  from  the  furnace.  A  little 
slag  is  also  left  in  the  furnace,  to  obviate  the  corrosive 
action  of  the  ore  upon  the  hearth.  The  matt  is  usually 
allowed  to  flow  into  the  tank  of  water  already  described, 
where  it  is  granulated.  As  soon  as  it  is  cooled  suffi- 
ciently, it  is  raised  out  of  the  tank*and  removed  to  the 
storehouse,  to  await  the  next  operation.  When  it  has 
26* 


306  COPPER  SMELTING. 

all  flowed  out,  or  sometimes  while  it  is  still  running 
from  the  furnace,  a  fresh  charge  is  introduced,  which  is 
worked  in  precisely  the  same  way. 

Two  men  at  a  time  manage  this  furnace,  which  works 
day  and  night  throughout  the  week.  Each  pair  of  men 
has  charge  of  it  during  twelve  hours.  On  Saturday 
night,  the  furnace  is  put  on  what  is  called  "dead  fire," 
for  Sunday — that  is,  it  is  merely  kept  hot,  without  being 
charged  with  fresh  ore.  On  Monday  morning,  or  Sun- 
day night,  according  to  the  regulations  of  the  works, 
it  is  again  charged  and  kept  at  work  for  another  week. 
The  night  work  is  taken  alternately  by  the  men,  who 
are  paid  by  the  ton,  and  are  not  allowed  anything  for 
working  over  their  foul  slag. 

The  chemistry  of  these  operations  is  very  simple.  The 
principal  change  which  takes  place  is  the  formation  of  a 
silicate  of  iron  and  the  expulsion  of  sulphur.  There  is 
usually  enough  silica  in  the  ores  to  take  up  as  much  of 
the  iron  as  is  desired.  When  this  is  not  the  case,  quartz 
sand  is  added.  Iron  has  a  strong  tendency  to  unite  with 
silicic  acid  at  high  temperatures,  especially  when  the 
oxide  is  brought  into  intimate  admixture  with  silica  by 
means  of  a  fusible  flux.  Silicate  of  iron  and  fluor  spar 
combined,  answer  this  purpose  admirably  well.  The 
oxygen  gas  of  the  air  passing  over  the  fused  materials 
burns  off  the  sulphur,  and  converts  the  iron  into  an  oxide 
which  unites  with  the  silicic  acid.  The  evolution  of  gases 
causes  a  commotion  which  greatly  facilitates  the  opera- 
tion. Fluor  spar  acts  by  parting  with  its  fluorine  to  sili- 
ca which  should  be  in  excess,  forming  volatile  flouride  of 
silicium,  which  bubbles  up  through  the  mass.  It  mixes 
the  materials  well,  and  renders  the  slag  fluid  by  the  for- 


COPPER  SMELTING.  307 

mation  of  another  silicate,  that  of  lime,  thus  preventing 
the  stiffening  of  the  slags  by  an  excess  of  silica.  It  gets 
rid  of  this  excess  by  removing  a  portion  of  it  directly, 
in  a  volatile  gas,  and  by  forming  a  fusible  silicate  with 
another  portion.  Limestone  acts  only  in  the  latter  way. 
It  is  evident  that  both  are  useful  chiefly  where  there  is 
too  much  silica  for  the  iron. 

The  resulting  matt  is  a  mixture  of  sulphuret  and  a 
little  oxide  of  jcppper  with  sulphuret  of  iron  and  small 
quantities  of  other  metals.  The  earthy  matters,  some 
of  the  sulphur,  and  much  of  the  iron  have  been  separated 
in  the  slag  or  the  volatile  products. 

Third  Operation. — The  granulated  matt  is  charged 
into  a  furnace  precisely  similar  to  that  used  for  calcining 
the  ore.  Care  is  taken  to  prevent  the  fusion  of  the  matt, 
which  would  prevent  the  proper  action  of  the  air.  For 
this  reason,  the  heat  is  kept  down  at  first  and  gradually 
pushed  towards  the  close  of  the  operation,  which  lasts 
about  twenty-four  hours.  During  this  time,  the  matt  is 
rabbled  every  two  hours  in  order  to  change  the  surfaces 
and  expose  the  sulphurets  freely  to  the  action  of  the 
atmosphere.  At  the  close  of  the  operation,  the  furnace 
should  have  attained  a  bright  red  heat.  To  effect  this 
roasting,  thirty-three  hundred  weight  of  coal  are  used. 

The  metal  has  now  changed  from  a  dark,  reddish  gray 
to  a  brownish  black,  and  has  become  more  friable.  The 
chemical  alteration  consists  in  the  further  oxidation  of 
the  metals  and  the  expulsion  of  still  more  sulphur.  The 
loss  of  weight  is  not  considerable,  because  oxygen  has, 
to  a  great  extent,  taken  the  place  of  sulphur.  Thus, 
1000  parts  of  crude  metal  will  furnish  974  of  calcined 
metal,  and  270  of  sulphurous  and  sulphuric  acids. 


308  COPPER  SMELTING. 

Fourth  Operation. — The  object  of  this  operation,  which 
is  performed  upon  the  calcined  coarse  metal,  is  to  sepa- 
rate, as  far  as  possible,  the  iron  from  the  sulphuret  of 
copper.  It  is  usually,  however,  not  confined  to  this 
simple  and  direct  melting,  but  advantage  is  taken  of  it 
to  work  down  other  ores  of  the  fourth  class,  which  con- 
tain little  sulphide  of  iron,  and  are  rich  in  copper  in 
the  state  of  sulphide  and  oxide,  as  well  as  the  rich  scoriae 
from  the  upper  furnaces.  It  requires  no  little  skill  so  to 
blend  the  heterogeneous  materials  of  this  charge  as  to 
produce  a  satisfactory  result.  There  are  smelted  in  this 
furnace,  not  only  the  calcined  metals,  rich  ores,  and 
scoriae,  but  also  the  various  sandy  and  calcareous  mat- 
ters from  the  walls  and  soles  of  furnaces  which  may  have 
become  impregnated  with  copper.  The  table  will  give 
some  idea  of  their  usual  proportions : 

Calcined  coarse  metal  from  the  third  operation,    .  559 

Crude  ores, 243 

Copper  scales  from  the  rolling  mills,  &c.,     .          .  7 

Scoria  from  the  ninth  operation,           ...  60 

Scoria  from  the  tenth  operation,  ...  24 
Furnace  waste  (cobbing)  from  the  second  to  the 

tenth  operations,          .....  60 

Earthy  matters,  sand  impregnated  with  copper,     .  41 

Earthy  matters,  bricks  impregnated  with  copper,  6 

1000 

It  will  be  understood,  of  course,  that  this  table  is  intend- 
ed to  give  merely  an  approximate  idea  of  these  propor- 
tions, as  it  is  very  evident  that  the  working  of  substances 


COPPER  SMELTING.  309 

so  very  various  in  their  composition  and  metallic  con- 
tents, cannot  be  carried  on  by  any  fixed  formula,  but 
must  vary  with  their  changing  constitution.  The  crite- 
rion for  the  workman  is  the  practical  result  of  the  first 
charge.  He  may  succeed  in  getting  a  fine  sulphuret  of 
copper  with  a  comparatively  clean  slag  at  the  first  trial, 
but  he  may,  on  the  other  hand,  produce  a  metal  con- 
taining a  large  proportion  of  sulphuret  of  iron,  and  a 
slag  in  which  there  is  a  good  deal  of  oxide  of  copper. — 
It  is  generally  believed  that  the  best  results  are  attained 
where  there  remains  in  the  matt  a  little  iron,  say  from 
four  to  ten  per  cent.,  and  from  three  to  five  per  cent,  of 
copper  pass  off  in  the  slag.  This  does  not  interfere  with 
the  success  of  the  work,  as  these  slags  are  all  smelted 
over  again  in  the  lower  furnaces,  where  the  copper  is  re- 
covered. It  is,  however,  necessary  to  guard  against  an 
excess  of  this  oxide  of  copper  in  the  slag,  as  it  will  re- 
act upon  the  sulphuret  and  produce  metallic  copper, 
which  is  not  desirable  at  this  stage  of  the  process,  since 
it  would  deteriorate  the  product. 

The  furnace  in  which  these  operations  are  performed, 
resembles  that  devoted  to  the  second  fusion,  except  that 
there  is  no  cavity  in  the  hearth,  but  a  gentle  slope  to- 
wards the  side  at  which  the  fused  material  is  run  out. 
The  fire  is  managed  in  the  same  way,  but  the  heat  is 
greater  on  account  of  the  greater  consumption  of  fuel. 
The  materials  are  introduced  either  through  the  hopper 
or  the  side-door,  the  larger  portions,  especially  the  sco- 
riae being  thrown  through  the  door.  They  are  then 
spread  evenly  over  the  sole  of  the  furnace.  The  charge 
weighs  about  thirty-two  hundred  weight. 


310  COPPER  SMELTING. 

The  doors  are  now  closed  and  luted,  and  the  fires 
regulated  so  as  to  calcine  the  surface.  In  about  an  hour 
the  mass  begins  to  soften  and  evolve  a  good  deal  of  gas, 
arising  from  double  decomposition,  and  in  about  three 
hours  after  charging,  the  fusion  is  nearly  completed, 
the  furnace  presenting  the  appearance  of  a  bath  upon 
which  the  unmelted  matter  floats.  In  about  four  hours 
from  the  time  of  charging,  the  matter  adhering  to  the 
walls  of  the  furnace  is  raked  down  and  the  whole  mass 
well  rabbled.  In  a  short  time,  the  fire  being  pushed, 
the  contents  of  the  furnace  are  in  a  state  of  tranquil 
fusion.  The  heat  is  still  gradually  raised  until  the  metal 
is  thought  to  be  sufficiently  purified,  which  generally 
happens  in  about  six  hours  from  the  time  of  charging. 
The  scoriae  are  raked  off  by  the  front  door,  and  the  fluid 
matt  tapped  out  at  the  side,  either  into  sand  moulds 
where  it  is  cast  into  pigs,  or  into  a  cistern  to  be  granu- 
lated. 

The  results  of  this  operation  are  a  white  metal,  which 
contains  but  little  foreign  matter,  being  a  nearly  pure 
sulphuret  of  copper,  and  slags  or  scoriae  which  are  brittle 
and  crystalline,  and  contain,  as  already  stated,  some 
oxide  of  copper.  In  Swansea,  a  special  operation  is  re- 
sorted to  for  the  purpose  of  recovering  the  copper  con- 
tained in  these  scoriae.  They  are  broken  to  pieces  and 
divided  in  two  lots,  of  which  the  poorer  is  worked  in  the 
first  fusion,  while  the  richer,  being  mixed  with  pulveriz- 
ed coal,  are  melted  to  obtain  their  metal,  which  is  white 
and  brittle.  The  scoriae  resulting  from  this  special  melt- 
ing are  partly  thrown  away  and  partly  employed  in  the 
first  fusion. 


COPPER  SMELTING.  311 

The  products  of  the  fourth  operation  have  been  stated 
in  the  following  manner : 

White  metal,     ....  402 

Poor  slag, 261 

Rich  slag, 281 

Furnace  waste,       ...  9 

Sulphurous  acid,     ...  43 

Water  and  Carbonic  acid,  4 

1000 

The  white  metal  is  grayish  white  or  blueish,  with  a 
strong  metallic  lustre,  containing  many  small  cavities 
which  are  often  lined  with  copper.  Its  composition  is : 

Copper,    .     .     .73. 
Iron,  ....     6.5 
Sulphur,  .     .     .  20.5 


100.0 

Sometimes  there  is  only  fifty  per  cent,  of  copper  in  it, 
but  this  is  below  the  standard. 

Fifth  Operation. — The  usual  routine  hitherto  followed 
in  the  several  processes,  in  dealing  with  the  ore,  is  in- 
terrupted here,  and  the  product  of  the  fourth  fusion  is 
not  used,  but  only  substances  of  a  different  nature  and 
class,  hence,  to  tabulate  the  course  of  procedure  in  the 
way  in  which  the  above  order  indicates,  would  appear 
contradictory  and  confusing ;  but  it  is  customary  in  the 
copper  foundries  of  Swansea,  to  adopt  this  plan  of  work- 
ing fresh  materials  with  the  slag  and  various  other  mat- 
ters containing  copper,  and  to  bring  the  valuable  matter 


312  COPPER  SMELTING. 

in  them  into  a  fit  state  to  undergo  the  same  operation  as  the 
product  resulting  from  the  last  fusion,  an  operation  to 
be  described  under  the  ninth  stage.  There  is  another 
purpose  in  view  and  this  is  the  production  of  a  better 
quality  of  copper.  Rich  foreign  ores  and  matt  which 
are  imported  into  Swansea,  if  mixed  with  the  ordinary 
productions  of  Cornwall,  would  give  a  metal  only  of 
medium  quality,  having  some  good  but  many  bad  quali- 
ties. It  is  the  practice,  in  these  cases,  to  work  only  the 
copper  ores  which  are  free  from  the  more  difficultly  eradi- 
cated impurities,  and  for  this  purpose  the  intermediate 
fifth,  sixth,  seventh  and  eighth  operations  are  added  to 
remove  the  copper  from  the  ore  and  the  slags  formed  in 
the  state  of  white  or  blue  metal.  Three  of  these,  the 
fifth,  seventh  and  eighth,  are  grouped  together  under  the 
designation  of  the  extra  process,  to  distinguish  them  from 
the  ordinary  course,  which  would  link  the  fourth  and 
ninth  operations  together.  Both  are,  however,  intimately 
connected  in  more  ways  than  one ;  for  instance,  the  ma- 
terial used  is  identical  with  the  product  of  the  second 
fusion  or  coarse  metal ;  this  union  is  brought  closer  by 
the  use  of  the  richer  slags  from  the  last  operation. 

When  they  have  undergone  another  fusion,  the  result- 
ing matt  of  white  metal  is  submitted  to  the  seventh  and 
eighth  fusions,  as  well  as  that  derived  from  the  extra 
product  of  the  fusion  under  consideration,  and  the  whole 
is  treated  in  the  ninth  operation  indiscriminately.  Indeed 
these  several  stages  for  enriching  the  matt,  although 
they  bring  about  reactions  more  efficacious  towards  re- 
moving the  substances  which  might  deteriorate  the  cop- 
per than  the  fusion  in  the  fourth  one,  still  are  nearly 


COPPEK  SMELTING.  313 

identical  with  the  latter  and  with  the  ninth  operation  yet 
to  be  described.  This  is  especially  the  case  in  regard  to 
the  fifth  fusion,  which  is  only  a  modification  of  the  pre- 
ceding one,  and  the  roasting  in  number  seven  and  eight 
are  merely  repetitions  of  the  ninth  method. 

The  material  employed  here  is,  as  already  stated, 
chiefly  composed  of  calcined  matt  from  the  purer 
variety  of  ores ;  but,  in  general,  a  quantity  of  the  ordi- 
nary substance  resulting  from  the  second  calcination,  is 
taken  and  incorporated  with  other  materials,  in  the 
annexed  ratio : — 

Calcined  coarse  metal  from  third  operation,  0.722 

Calcined  ore  of  the  second  or  third  class,   .  0.185 

Earthy  matter — silicious,  .         .         .  0.084 

"          "          bricks,    ....  0.009 


1.000 

The  furnace  in  which  the  process  is  conducted,  is 
identical  in  form  with  that  used  for  the  last  fusion;  if 
the  composition  of  fuel  is  in  this  as  in  the  foregoing, 
composed  of  anthracite  and  caking  coal.  The  time 
occupied  in  working  the  charge  is  about  six  to  seven 
hours,  making  twenty-two  charges  per  week.  Like  the 
substances  used  in  the  fourth  operation,  these  undergo 
a  gradual  fusion,  which,  toward  the  close,  becomes  urged 
by  a  very  high  heat.  Very  little  change  is  exerted  till 
the  matter  becomes  liquefied,  when  the  oxide  of  copper 
reacts  upon  the  sulphides  of  iron,  giving  rise  to  a  sul- 
phide of  copper  and  an  oxide  of  iron,  which  enters  into 
combination  with  the  silicious  matter,  and  generates  a 
27 


314  COPPER  SMELTING. 

very  fusible  scoria.  Sulphurous  and  sulphuric  acids  are 
likewise  liberated:  but  a  portion  of  the  sulphur  is  sub- 
stituted for  the  oxygen  derived  from  the  oxide  of  copper, 
thus  converting  the  whole  of  the  latter  into  a  sulphide. 
This  constitutes  the  refining  process  which  is  chiefly 
intended  in  this  operation,  namely,  the  removal  of  the 
iron  and  excess  of  sulphur,  leaving  the  copper  combined 
with  the  least  quantity  of  the  latter  element.  The  weight 
of  the  charge  is  two  tons ;  and  the  results  after  the  fusion 
may  be  expressed  as  in  the  annexed  table : — 

Blue  metal  for  the  seventh  operation,          .  0.495 

Scoria  for  the  second  operation,         .         .  0.434 

Furnace  waste  for  the  fourth  operation,      .  0.008 

Sulphurous  acid,       .....  0.056 

Oxygen, 0.007 

1.000 

After  the  charge  is  worked  off,  the  matter  closing  the 
tap-hole  is  completely  removed,  and  the  cupreous  fluid 
which  is  called  blue  metal,  permitted  to  flow  out  into 
moulds.  The  slag  is  then  permitted  to  run  out  of  the 
same  orifice. 

Sixth  Operation. — In  this  stage,  the  slags  resulting 
from  the  preceding  and  the  two  succeeding  fusions,  and 
which  are  rich  in  oxide  of  copper,  as  well  as  some  rich 
sulphide  of  copper  from  certain  ores,  which,  however, 
are  free  from  injurious  substances,  are  treated.  The 
furnace  in  this  case  is  slightly  modified  to  suit  the 
material  which  is  being  operated  upon.  No  hopper  is 
appended,  in  consequence  of  the  substance  being  in  too 


COPPER  SMELTING.  315 

large  pieces  to  conveniently  pass  through ;  but  a  charg- 
ing door  is  formed  in  one  side ;  and  when  the  lumps  of 
scoria  are  injected,  very  little  exertion  is  required  to 
spread  them  evenly  over  the  sole  of  the  furnace.  During 
the  succeeding  treatment,  this  door  is  kept  closed  and 
luted  at  the  sides,  so  that  no  air  can  enter.  When  the 
matt  is  ready,  it  is  drawn  off,  as  usual,  through  an  ori- 
fice for  the  purpose,  made  at  the  extremity  of  the  trans- 
verse diameter  of  the  hearth,  opposite  the  side  in  which 
the  charging  takes  place.  The  medium  of  heat  is  the 
same  in  this  as  in  the  other  furnaces,  and  the  time  occu- 
pied in  working  extends  to  about  five  hours  and  a  half. 
As  the  quantity  of  oxide  of  copper  in  the  scoria  employed 
cannot  be  wholly  converted  into  sulphide  of  copper  by  the 
action  of  the  sulphur  combined  with  the  iron  in  the  ore 
added,  it  is  reduced  to  the  metallic  state,  and  afterwards 
purified  in  the  succeeding  treatments.  This  is  brought 
about  by  adding  to  the  substance  slack,  or  ground  coal 
or  charcoal;  the  results  of  this  reaction  are  carbonic 
acid  and  metallic  copper,  which,  owing  to  its  greater 
gravity,  penetrates  the  scoria  and  matt,  and  forms  a 
layer  of  impure  black  copper,  or  bottoms,  on  the  hearth. 
In  this  behaviour  the  reduced  metal  effects  an  important 
part  in  purifying  the  matt  of  sulphide  of  copper ;  for  it 
reduces  and  precipitates  with  it  certain  portions  of  tin 
and  arsenic  which  are  present,  the  removal  of  which 
would  otherwise  be  difficult,  and  the  presence  of  which 
would  operate  deleteriously  upon  the  quality  of  the 
metal.  The  nickel  and  cobalt  which  sometimes  exist  in 
cupreous  minerals  are  in  like  manner  decomposed  and 
carried  down  in  the  black  copper,  their  sulphur  being 


316 


COPPER  SMELTING. 


transferred  to  a  portion  of  the  oxide  of  copper  in  the 
slag.  A  product  of  great  excellence  is  the  result  of 
these  various  depurating  reactions,  and  is  called  by  way 
of  distinction,  best  selected,  when  it  is  reduced,  and  while 
in  the  state  of  matt,  hard  metal. 

In  the  charge  for  this  furnace,  which  amounts  gene- 
rally to  two  tons,  the  several  substances  are  taken  in 
the  proportion  of  the  annexed  table,  or  thereabouts,  viz : 

Rich  slag  from  the  fourth  operation,  .  0.671 

"  "       seventh      "         .         .  0.095 

"  "       eighth        "         .         .  0.053 

Copper  pyrites, 0.079 

Sweeping  of  the  foundries  from  the  eighth, 

ninth,  and  tenth  operations,  .         .         .  0.055 

Carbon  employed  as  re-agent,  .         .         .  0.001 

Earthy  matters— sand,      ....  0.036 

"    *        "         brick,     ....  0.010 

1.000 

Details  of  working  similar  to  those  pursued  in  the 
fourth  fusion,  onlyM;hat  the  hearth  of  the  furnace  is  in 
this  instance  more  liable  to  corrosion,  because  sulphurous 
products  are  in  much  less  abundance,  and  the  scoria  and 
iron  react  upon  it,  abstracting  the  silica.  Such  is  the 
case,  especially  in  the  parts  adjoining  the  walls ;  but  as 
a  preventive,  the  slag  is  piled  round  in  these  parts,  and 
as  soon  as  the  matter  becomes  molten,  the  quartz,  which 
forms  a  considerable  part  of  the  ore  added,  supplies  sili- 
ceous matter  to  the  iron,  and  the  hearth  is  preserved. 

At   the   close  of  the   process,  the  fused   matter   is 


COPPER  SMELTING.  317 

three  layers ;  the  upper  is  constituted  of  the  scoria,  the 
middle  of  fused  matt,  and  the  lower  of  black  copper: 
these  are  drawn  off  as  usual.  These  products  may  be 
tabulated  as  under — 

White  metal  for  the  eighth  operation,         .  0.057 

Red  metal          "          "  «  0.016 

Tin  alloy, 0.005 

Copper  bases  for  operation,       .         .         .  0.008 

Slag  to  be  rejected,  ....  0.901 

Refuse  of  furnace  for  fourth  operation,      .  0.006 

Carbonic  acid, 0.003 

Water  and  carbonic  acid  from  ore,    .         .  0.001 


1.000 

Seventh  Operation. — Blue  metal  is  here  converted 
into  white  metal,  by  the  agency  of  the  air;  and  the 
chief  or  entire  part  of  the  remaining  iron  is  removed, 
by  forming  a  fusible  silicate  towards  the  close  of  the 
calcination.  The  furnace  which  is  requisite  for  this 
double  purpose  is  constructed  like  that  mentioned  under 
the  last  stage,  with  charging  doors  at  the  side  and  end, 
opposite  the  fire,  and  a  tap-hole  at  the  other  side  at  the 
end  of  the  middle  transverse  diameter.  In  addition  to 
these  air  is  admitted  by  openings  near  or  through  the 
bridge  of  the  hearth,  as  already  described  in  reference 
to  operations  for  roasting.  Crude  blue  metal  constitutes 
the  charge ;  but  it  carries  with  it  a  certain  quantity  of 
sand  from  the  moulds  wherein  it  was  cast,  and  during 
the  working  near  a  ton  of  the  materials  of  the  furnace 
are  disintegrated  and  carried  off  in  combination,  partly 
27* 


318  COPPER  SMELTING. 

with  the  iron  of  the  scoria,  so  that  the  components  of 
the  charge  may  be  represented  in  the  relative  propor- 
tion expressed  by  the  annexed  table,  viz : 

Blue  metal  from  fifth  operation,         .  .  0.789 

Furnace  waste,  &c. — sand,         .         .  .  0.108 

"                "            bricks  and  clay,  .  0.006 

Oxygen  derived  from  the  air,    .         .  .  0.097 

1.000 

Two  tons  of  the  blue  metal,  or  sulphide,  are  intro- 
duced carefully  at  the  side  and  end  doors  above  referred 
to,  the  temperature  of  the  interior  being  somewhat 
reduced  in  order  not  to  effect  the  fusion  of  the  sub- 
stance very  readily.  Care  must  likewise  be  taken  that 
the  bars  of  material  are  deposited  within  the  furnace  as 
perfect  as  possible,  in  order  that  they  may  present  in- 
terstices for  the  flame  and  oxidizing  current  to  pass 
through,  which  will  thereby  effect  a  better  roasting  than 
could  be  done,  were  the  charge  in  small  fragments.  As 
the  blue  metal  is  brittle,  it  is  customary  to  employ  a 
kind  of  tool  not  very  unlike  a  baker's  peel,  and  which  is 
worked  by  four  persons  for  introducing  it.  It  is  kept 
at  some  distance  from  the  bridge  of  the  fire,  as  near  this 
it  would  meet  little  of  the  flame ;  for  this  reason,  about 
two  and  a  half  to  three,  or  even  four  feet  are  reserved 
between  the  matter  operated  upon  and  the  fire  bridge. 
The  heat  applied  in  this  case  is  during  the  first  part  of 
the  operation  is  very  moderate,  but  in  proportion  as  the 
sulphur  is  eliminated,  and  the  oxidation  of  the  metals 
proceeds,  it  is  increased,  till  in  the  end,  it  is  raised  suf- 


COPPER   SMELTING.  319 

ficiently  to  bring  the  charge  into  a  fluid  state.  By  this 
routine,  the  iron,  which  alone  had  been  oxidized  during 
the  roasting,  is  combined  with  the  silica,  and  forms  a 
fusible  slag,  which  is  removed  after  drawing  off  the  matt 
of  white  metal. 

The  results  of  the  charge  are  proportionally  expressed 
in  the  annexed  table: — 

"White  metal  for  the  eighth  operation,          .  0.588 

Poor  slag  for  the  second  operation,   .         .  0.103 

Furnace  waste  for  the  fourth  operation,     .  0.008 

Sulphurous  acid,       .....  0.124 


1.000 

Eighth  Operation. — This  seems  to  be  only  a  repeti- 
tion of  the  preceding  treatment,  and  is  conducted  in 
almost  the  same  manner.  It  constitutes  the  last  of  the 
series  called  the  extra-process,  and  yields  a  substance 
which,  like  that  resulting  from  operation  four,  in  the 
ordinary  mode,  is  ready  for  the  calcination  by  which  the 
metal  is  obtained.  The  charge  weighs  about  one  ton 
and  a  half,  and  the  time  of  working  extends  over  seven 
or  eight  hours. 

Two  stages  are  observed  in  it :  first,  the  roasting, 
by  which  a  still  further  quantity  of  sulphur  is  expelled, 
and  oxide  of  copper,  with  sesquioxide  of  iron,  is  pro- 
duced ;  and,  secondly,  the  fusion  of  the  mass,  as  before 
detailed,  by  which  any  iron  may  be  separated  in  the 
scoria.  A  reduction  of  some  of  the  oxide  of  copper 
contained  in  the  slag  is  likewise  effected ;  when  it  comes 
in  contact  with  the  matt  of  rich  white  metal,  it  yields 


320  COPPER  SMELTING. 

oxygen  to  the  sulphur  in  combination,  and  gives  rise  to 
the  formation  of  sulphurous  acid  and  the  precipitation 
of  metallic  copper. 

White  metal  from  the  seventh  division  is  usually  em- 
ployed alone,  especially  if  a  first  quality  of  copper  is  to 
be  produced ;  but  when  this  is  not  the  case,  the  matts 
procured  from  the  fifth  and  sixth  fusion  are  mixed  with 
it  in  the  ratio  tabulated  as  under : 

White  metal  of  the  seventh  operation,  .  0.712 

"         "         "         sixth           "  .  0.125 

Red  metal  of  the  sixth  operation,       .  .  0.034 

Earthy  matters  from  the  sole,      .       .  .  0.041 

"            "         "     brjck  and  clay,  .  .  O.OOT 

Oxygen  from  the  atmosphere,       .      .  .  0.081 


1.000 

After  the  calcination  is  carried  on  with  a  gradual  in- 
crease of  temperature  for  about  three  hours  and  a  half, 
the  roasting  is  considered  to  be  thoroughly  performed  ; 
the  fire  is  then  urged,  and  the  matter  melted,  and  by 
this  means  a  further  quantity  of  sulphurous  acid  is  libe- 
rated, in  consequence  of  the  action  of  the  excess  of 
oxide  of  copper  in  the  slag  upon  the  matt  of  sulphide 
of  copper,  by  which  the  sulphur  is  oxidized,  and  a  pro- 
portionate weight  of  metal  precipitated.  This  precipi- 
tation of  copper  aids  considerably  in  refining  the  matt 
of  any  portions  of  arsenic,  tin,  &c.,  which  may  be  con- 
tained in  it,  and  which  it  carries  with  it  to  the  bottom. 
During  the  three  hours  and  a  half  fusion,  these  changes 
are  being  instituted;  and  at  the  close,  the  charge  is 


COPPER  SMELTING.  321 

found  separated  into  three  distinct  layers.  Of  these,  the 
upper  one  consists  of  scoria,  mixed  with  oxide  of  copper ; 
the  middle  of  the  pure  matt  or  regulus ;  and  the  under 
one,  of  bottoms,  or  an  alloy  of  copper  and  tin,  with  an 
admixture  of  more  or  less  matt.  This  is  shown  in  the 
annexed  statement  of  results: 

Regulus  of  metal  seven  for  the  ninth  operation,  0.528 

"  "          six         "          "          "  0.112 

Cupreous  base  from  seven,         .         .         .  0.088 

"         "         "          six,         .         .         .  0.020 

Slags  to  be  used  again  in  the  sixth  operation,  0.118 

Furnace  waste         "         "     fourth        "  0.004 

Copper  sweepings,  "         "     sixth          "  0.002 

Sulphurous  acid,       .....  0.128 

1.000* 

Ninth  Operation.  At  this  stage  of  our  description, 
we  come  back  to  the  regular  course  of  the  smelting, 
which  we  left  in  order  to  describe  a  series  of  processes 
intended  to  bring  into  the  final  operations  a  class  of 
substances  which  are  continually  accumulating  about  a 
smelting  establishment.  The  last  of  these,  which  we 
have  called  number  eight,  has  produced  a  result  which 
may  be  mixed  with  the  white  metal  from  the  fourth  ope- 

*  I  have  quoted  this  entire  description  of  the  extra  process  from  the 
excellent  article  on  Copper,  in  Muspratt's  Chemistry,  because  it  is  the 
fullest  and  most  satisfactory  account  of  the  Welsh  method  of  working 
up  the  residues  from  the  furnaces,  and  the  various  cupreous  matters 
which  accumulate  about  a  copper  work.  They  are  treated  in  this  way, 
because  they  would  not  be  advantageously  smelted  in  the  regular  course. 
It  is  only  employed  when  these  matters  have  considerably  accumulated. 


COPPER  SMELTING. 

ration,  or  worked  by  itself  for  pig  copper.  Up  to  this 
stage,  the  smelter  has  been  availing  himself  of  two  sets 
of  reactions — that  between  sulphur  and  oxygen,  and 
that  between  silica  and  oxide  of  iron.  There  has  been 
a  continual  process  of  oxidation  resulting  in  the  forma- 
tion of  sulphates  of  the  two  metals.  As  the  iron  salt  is 
more  rapidly  decomposed  than  that  of  copper,  we  have 
a  quantity  of  oxide  of  iron  in  the  bath  of  molten  mat- 
ter that  fills  the  furnace.  This  oxide,  having  a  strong 
affinity  for  silica  at  a  high  temperature,  combines  with 
that  substance  to  form  a  fusible  slag.  The  sulphate 
and  oxide  of  copper  reacting  on  the  undecomposed  sul- 
phuret,  produce  sulphurous  acid,  which  burns  off,  and 
sulphuret  of  copper,  with  a  minimum  degree  of  sulphu- 
ration,  called  by  the  smelters  white  metal,  so  that  at 
this  stage  we  may  consider  a  large  portion  of  the  sul- 
phur, and  nearly  all  the  iron,  finally  separated.  It 
remains  now  to  get  rid  of  the  remaining  sulphur. 
1  When  no  iron  whatever  is  present,  a  simple  roasting 
and  smelting,  under  proper  management,  will  dissipate 
the  remaining  sulphur.  If,  however,  some  iron  remain, 
it  will  be  necessary  to  add  some  silicious  matter,  in  order 
to  combine  with  the  oxide  of  that  metal,  and  thoroughly 
to  purify  the  copper.  As  it  is  rarely  the  case  that  all 
the  iron  is  separated  in  the  fourth  operation,  it  is  cus- 
tomary to  add  to  this  charge  some  rich  quartzose  ores. 
Hence  it  will  be  seen  that  there  are  two  objects  to  be 
accomplished  in  this  process — one  to  roast  the  sulphur 
off  by  the  direct  action  of  the  atmosphere,  aided  by  the 
double  decomposition  going  on  between  the  sulphuret 
and  oxide  of  copper ;  the  other  to  get  rid  of  iron  by 


COPPER  SMELTING.  323 

oxidating  it  and  then  combining  it  with  silica.  To  ac- 
complish these  ends,  the  smelter  divides  this  operation 
into  four  distinct  stages.  In  the  first,  he  roasts  the 
material,  by  heating  it,  with  free  access  of  air ;  in  the 
second  and  third,  he  manages  the  mutual  decomposition 
of  the  oxide  and  sulphuret  of  copper ;  in  the  fourth,  he 
produces  metallic  copper,  effects  the  union  of  the  oxide 
of  iron  with  silica,  and  withdraws  the  slag. 

The  furnace  in  which  this  operation  is  performed, 
resembles  the  other  smelting  furnaces,  having  a  side 
door,  an  end  door,  and  a  tap  hole  opposite  the  former. 
The  charge  is  from  three  to  three  and  a  half  tons  of 
white  metal  and  regulus,  which  are  introduced  in  large 
masses,  and  piled  up  on  the  sole  of  the  furnace.  The 
openings  are  now  closed  and  luted,  and  the  heat  is 
raised.  The  combustible  gases,  as  they  sweep  over  the 
mass  of  metal,  gradually  deprive  it  of  much  of  its  sul- 
phur. If  the  furnace  be  watched  at  this  time,  little 
drops  will  appear  to  sweat  out  of  the  red  hot  pigs,  and 
trickle  down  to  the  sole  of  the  furnace.  In  this  slow, 
piecemeal  fusion,  abundant  opportunity  is  afforded  for 
the  oxidating  action  of  the  atmosphere.  This  first 
stage  of  the  process  lasts  about  four  hours,  and  is  com- 
pleted when  the  whole  charge  has  become  liquid. 

The  second  stage  now  begins.  A  seething,  or  boiling 
in  fine  bubbles,  is  now  apparent  throughout  the  entire 
bulk  of  the  charge.  Every  now  and  then  a  brilliant 
spot  is  seen  upon  one  of  these  little  bubbles,  and  indi- 
cates the  conversion  of  a  portion  of  it  into  metallic 
copper.  The  reaction  between  the  oxide  and  the  sul- 
phuret of  copper  is  now  going  on. 

This  is  completed  in  the  third  stage,  which  the  work- 


324  COPPER  SMELTING. 

man  inaugurates  by  throwing  open  the  doors,  and  admit- 
ting atmospheric  air,  taking  care  to  keep  the  fire  in 
such  a  condition  that  a  partial  closure  of  the  openings 
will  at  any  time  raise  the  contents  of  the  furnace  to 
the  necessary  temperature.  The  first  effect  of  the  cold 
air  is  the  formation  of  a  consolidated  film  over  the  whole 
bath.  Beneath  this  the  action  goes  on  violently,  the 
confined  gases  causing  rents  in  this  surface  layer,  and 
throwing  up  new  fluid  from  below.  Presently,  the 
cooled  layer  becomes  so  thick  and  tenacious  that  the 
gases  cannot  escape  freely,  but  cause  a  great  swelling 
of  the  mass,  together  with  an  agitation  that  effects  the 
most  thorough  intermingling  of  the  liquid  contents. 
This  evolution  of  sulphurous  acid  goes  on  for  ten  or 
twelve  hours,  at  the  end  of  which  time  the  mass  has 
cooled,  stiffened,  and  become  extremely  porous  on  ac- 
count of  the  inability  of  the  gas  to  escape.  The  fire  is 
now  increased,  the  door  closed,  and  the  furnace  brought 
to  a  bright  red  heat.  The  mass  again  becomes  liquid, 
the  gases  are  expelled,  and  the  bath  begins  to  boil  with 
larger  bubbles,  so  lustrous  that  it  is  scarcely  possible 
to  look  at  them.  Six  hours  are  usually  taken  up  in  this 
fusion,  and  at  the  end  of  that  time,  the  sulphur  is  nearly 
all  gone 

All  this  time,  the  siliceous  matters  have  been  diffused 
throughout  the  mass  without  combining  with  the  ox- 
ides, because  the  heat  has  been  insufficient.  In  the 
fourth  and  last  stage,  however,  the  heat  is  raised  to  the 
highest  point,  and  kept  there  till  the  process  is  ended. 
The  silicate  of  iron  now  forms  a  fusible  slag,  which, 
being  lighter  than  the  copper,  rises  to  the  surface,  and 
floats  over  the  metallic  bath.  It  is  raked  off  at  the  end 


COPPER  SMELTING.  325 

door,  and  the  taphole  being  opened,  the  copper  flows 
out  into  moulds.  It  is  full  of  hubbies,  brittle,  with  a 
coarse,  granular  fracture,  the  freshly  broken  surface  be- 
ing of  a  deep  red  color  and  full  of  cavities. 

It  is  sometimes  called  blistered  copper,  from  its  blebby 
surface,  and  sometimes  pig  copper,  from  the  forms  in 
which  it  is  moulded.  The  slag  which  is  raked  off  from 
it,  contains  a  large  proportion  of  oxide  of  copper,  and 
not  a  little  of  the  same  in  a  metallic  state.  The  oxide 
is  both  in  the  form  of  a  silicate  and  mechanically  com- 
bined with  the  mass.  This  alone  is  worked  down  in  the 
fourth  operation. 

In  many  furnaces,  this  process  is  divided  in  two.  The 
white  metal,  of  the  fourth  operation,  is  oftener  sixty 
than  seventy-three  per  cent.,  and  its  roasting  in  the 
furnace  would  take  up  too  much  time,  and  be  imper- 
fectly effected.  It  has  been  found  advantageous,  there- 
fore, to  tap  out  this  substance  at  about  the  commence- 
ment of  the  third  stage  described  above.  As  it  flows 
from  the  furnace  in  a  thin  stream,  it  is,  of  course,  freely 
exposed  to  the  action  of  the  air,  and  is  very  effectually 
roasted.  Lying  in  its  sand  moulds,  it  speedily  chills 
upon  the  surface ;  but  in  the  interior  of  the  pigs,  the 
agitation  of  the  liquid  still  goes  on,  giving  rise  to  very 
interesting  volcanic  phenomena.  Numerous  small  open- 
in^s  are  made  in  the  film,  and  the  boiling  matter  from 
within  is  thrown  out.  It  falls  around  the  edges,  making 
little  irregular  cones,  which  rapidly  increase  in  height, 
till  they  resemble  so  many  chimneys  covering  the  pigs 
of  regulus.  Molten  matters  are  shot  out  by  the  intes- 
tine commotion,  far  above  their  summits,  and  little 
28 


32fi  COPPER  SMELTING. 

streams  of  lava  trickle  down  their  sides.  The  geologist 
might  gather  some  hints  as  to  the  action  of  volcanoes, 
by  studying  the  phenomena  of  these  little  elevations. 
The  regulus  thus  obtained,  is  often  immediately  charged 
back  into  the  same  furnace  from  which  it  was  tapped  out. 
The  copper  obtained  by  this  operation,  is,  as  we  have 
said,  coarse  and  brittle,  and  unfit  for  the  use  of  the 
mechanic.  It  still  contains  sulphur  and  other  matters, 
which  impair  its  tenacity.  These  are  expelled  in  the 
final  process,  which  we  are  now  about  to  describe. 

Tenth  Operation.  This  process  is  called  refining  or 
toughening,  and  brings  the  copper  to  a  marketable 
condition.  It  is  performed  in  a  furnace  resembling  the 
smelting  furnace,  except  that  the  grate  is  larger,  and  the 
arch  is  higher.  The  former  modification  is  necessary, 
because  a  greater  heat  is  required  than  in  the  preceding 
operations,  and  the  latter,  in  order  to  avoid  risk  of  oxi- 
dation, which  would  take  place  rapidly  under  a  low 
arch.  If  this  accident  were  to  happen,  the  refiner 
would  witness  what  is  called  the  rising  of  the  copper. 
The  film  of  oxide  on  the  surface  would  first  consolidate, 
then  crack,  and  the  liquid  metal  below  would  boil  over 
the  crust.  Copper,  in  this  condition,  would  be  unfit  to 
work,  because  it  would  not  laminate.  It  requires  a  spe- 
cial treatment. 

The  pigs  of  copper,  produced  in  the  last  operation, 
are  charged  into  this  furnace  by  means  of  a  peel.  These 
are  carefully  arranged  so  as  to  present  a  large  surface 
to  the  action  of  the  fire,  and  to  allow  the  draught  to  pass 
through  them.  The  amount -of  the  charge  varies  from 
three  to  six  tons,  and  in  some  places,  it  is  said  that  ten 
tons  have  been  worked.  The  heat  is  now  kept  up  for 


COPPER  SMELTING.  327 

about  eighteen  hours,  during  which  time  the  copper  is 
calcining,  the  metal  having  melted  in  the  first  six  hours. 
The  foreign  metals  and  a  good  deal  of  the  copper  itself, 
are  oxidated  and  combine  with  the  silica,  which  is  always 
present,  in  the  shape  of  sand  adhering  to  the  pigs,  and 
furnace  waste.  The  oxide  of  copper  assists  the  scori- 
fication  of  the  other  metals,  which  separate  and  rise  to 
the  surface  with  the  slag.  The  heat  is  now  increased 
awhile  to  ensure  a  proper  fusion  of  the  scoria,  which 
is  then  raked  off.  This  scoria  is  heavy  and  compact, 
of  a  dark  or  ruby  red  tint,  due  to  the  suboxide  of  copper, 
and  filled  with  filaments  and  beads  of  metallic  copper. 

At  this  stage  the  metal  is  ready  for  refining.  It 
is  now  dry,  as  the  workmen  term  it,  and  contains  a 
quantity  of  oxide  of  copper  diffused  through  it.  Its  color 
is  a  deep  red  approaching  to  purple,  its  texture  coarse, 
open  and  crystalline,  and  its  tenacity  very  slight.  At 
this  time  the  refiner  commences  taking  his  tests  or  assays. 
He  has  a  long  handled  ladle  with  a  small  bowl,  which 
he  dips  into  the  melted  metal.  He  then  withdraws  it, 
suffers  it  to  harden  upon  the  surface  and  plunges  it 
into  water  to  cool  it.  He  cuts  it  partly  through  with  a 
chisel,  and  then  he  breaks  it,  forming  his  opinion  of  the 
state  of  the  copper  by  its  color,  its  texture  and  its  lustre. 

If  the  metal  were  left  uncovered  at  this  high  temper- 
ature, it  would  speedily  absorb  still  more  oxygen  than  is 
already  combined  with  it.  To  prevent  this,  the  refiner 
covers  the  surface  with  charcoal,  which  as  it  burns  off 
absorbs  the  combined  oxygen  from  the  metallic  bath. 
This  action  however,  is  .confined  to  the  surface  of  the 
metal,  as  is  that  of  the  billets  of  green  wood  which  are 
now  thrown  on.  To  reach  the  centre  of  the  charge, 


328  COPPER   SMELTING. 

s  tout  poles  of  green  wood  are  thrust  below  the  surface  of 
the  metallic  bath,  where  they  burn  at  the  expense  of  its 
oxygen.  The  ebullition  produced  by  the  escape  of  the 
gases,  causes  a  thorough  intermingling  of  the  constitu- 
ents of  the  bath,  and  brings  every  particle  of  it  in 
contact  with  the  deoxidizing  agents.  This  poling,  as  it 
is  called,  continues  for  twenty  minutes  or  half  an  hour. 
The  refiner  takes  repeated  tests  during  this  process.  If 
the  broken  surface  is  dull  and  of  a  purplish  or  brick  red, 
he  knows  that  there  is  still  some  oxide  of  copper  mixed 
with  the  pure  metal.  When  the  refining  is  complete, 
the  broken  surface  of  the  assay  has  a  fine  light  red  color, 
and  a  soft  satiny  lustre ;  as  soon  as  this  point  is  attained, 
the  refiner  orders  the  poles  to  be  withdrawn.  Should 
it  be  allowed  to  remain  only  a  few  minutes  longer,  an 
unfavorable  change  takes  place.  The  copper  absorbs 
carbon,  and  becomes  even  more  brittle  than  before  it 
was  refined  at  all.  The  assay  reveals  this  condition  of 
the  bath.  Its  color  is  a  brilliant  yellowish  red,  its  frac- 
ture fibrous  and  striated,  and  its  grain  coarse.  When 
this  happens,  the  charcoal  is  pushed  back  and  the  doors 
of  the  furnace  are  thrown  open  to  admit  the  air,  which 
burns  off  the  excess  of  carbon  and  restores  the  copper 
to  its  maleable  condition.  On  the  other  hand,  if  the 
charcoal  be  not  kept  over  the  face  of  the  bath,  it  absorbs 
oxygen  from  the  air  and  returns  to  its  dry  state.  The 
remedy  for  this  is  a  fresh  application  of  the  green  wood. 
In  the  former  case,  the  workmen  say  that  the  copper 
has  gone  too  far  or  that  it  is  over  pitch,  in  the  latter  it 
has  gone  back  or  is  under  pitch. 

It  often  happens  that  a  difficulty  occurs  in  separating 
the  foreign  metals  from  the  copper.     This  is  overcome 


COPPER  SMELTING.  329 

by  the  use  of  lead,  which  is  an  admirable  scorifier  and 
forms  fusible  compounds  with  the  different  metallic 
oxides,  which  rise  to  the  surface  and  are  raked  off  with 
the  slag.  To  accomplish  this,  it  is  necessary  to  rabble 
the  bath  completely,  so  as  to  bring  all  the  lead  under  the 
influence  of  the  oxygen,  that  it  may  all  be  found  in  the 
slag.  If  any  be  allowed  to  remain  in  its  metallic  state, 
it  has  a  very  bad  effect  upon  the  subsequent  rolling  of 
the  copper,  in  causing  the  scale  to  adhere  to  the  surface 
and  preventing  the  proper  cleansing  of  the  sheets. 

The  refining  being  completed,  the  men  dip  the  copper 
out  of  a  depression  in  the  sole  of  the  furnace  just  behind 
the  end  door.  For  this  purpose  they  use  iron  ladles 
lined  with  clay.  The  metal  is  usually  cast  in  ingots,  in 
moulds  made  of  copper.  As  soon  as  these  ingots  have 
consolidated,  they  are  thrown  into  water.  This  gives 
them  a  slight  film  of  sub-oxide  which  adds  to  the  beauty 
of  their  appearance.  If  allowed  to  remain  too  long 
exposed  to  the  air,  before  being  plunged  into  water, 
they  are  coated  with  a  scale  of  the  black  oxide  which 
makes  them  rough  and  unsightly.  When  required  for  the 
rolling  mill,  the  molten  metal  is  cast  into  plates  or  bars. 

Muspratt  gives  the  following  tables  as  representing 
the  charge  and  its  results. 

Charge. 

Coarse  Copper, 0.954 

Earthy  Matters,  Sand,  -         -        -         0.013 

«  "        Brick  and  Clay,  -         -         0.021 

Oxygen  of  the  air,         -.      -'./.  ' -.       -         0.012 

1.000 

28* 


odO  COPPER  SMELTING. 

Results. 

Saleable  Copper,  -        -         -  0.908 

Slag  for  Operation,  four,       -  0.055 

Furnace  "Waste,          "...  0.022 

Copper  Sweepings,     "...  0.002 

Sulphurous  Acid.          -        -        -        -  0.013 

1.000 

In  the  foregoing  account  of  the  processes  adopted  at 
Swansea,  I  have  chiefly  followed  Muspratt,  who  has 
given  us  the  most  recent  and  one  of  the  fullest  and 
most  satisfactory  descriptions  of  this  elaborate  system  of 
smelting.  It  must  not  be  supposed,  however,  that  the 
routine  there  described,  is  servilely  followed  in  all  the 
establishments  for  copper  smelting  on  the  Welsh  plan, 
much  depends  upon  the  kind  of  ore  which  is  to  be  heated, 
much  also  upon  the  nature  of  the  fuel.  The  extra  pro- 
cess, intervening  between  the  fourth  and  ninth  opera- 
tions, is  often  omitted,  the  substances  to  which  it  is 
chiefly  devoted,  being  smelted  in  small  quantities  at  the 
suitable  stages  of  the  regular  process.  At  many  works, 
the  product  of  the  fourth  operation,  or  the  first  smelting 
after  the  calcination  of  the  metal  from  the  ore-furnace, 
has  not  reached  the  stage  of  white  metal.  In  that  case 
it  undergoes  a  calcination  to  bring  it  up  sufficiently  for 
smelting  so  as  to  obtain  regulus  or  black  copper.  In 
this  country,  where  the  ores  smelted  by  this  method 
under  consideration,  are  richer,  and  rarely  contain  either 
arsenic,  antimony  or  tin,  the  preliminary  calcination  is 
commonly  omitted.  The  ores  are  thrown  raw  into  the 
furnace,  and  calcination  is  performed  upon  the  coarse 


COPPER  SMELTING.  331 

metal  obtained  from  them.  This  is  then  run  down  into 
white  metal  and  the  rest  of  the  plan,  with  the  exception 
of  the  extra  process,  goes  on  as  we  have  described. 
Under  some  circumstances,  the  calcination  of  the  coarse 
metal  is  omitted.  Then,  this  product  is  introduced  into 
a  smelting  furnace  and  subjected  to  roasting  and  fusion 
which  produces  Hue  metal.  This,  in  its  turn,  is  roasted 
and  smelted  in  a  similar  manner,  to  produce  white  metal. 
There  are  still  further  modifications  sometimes  adopted, 
the  whole  depending  upon  the  nature  of  the  materials 
submitted  to  the  smelter.  The  skill  of  the  master  work- 
man is  shown  in  adapting  these  processes  to  the  requi- 
sitions of  his  particular  work. 

There  is  often  a  notable  proportion  of  silver  contained 
in  the  copper  ores  worked  at  Swansea.  This  is  some- 
times entirely  neglected.  There  are  works  however, 
erected  for  the  separation  of  the  more  precious  metal. 
In  these,  various  plans  are  pursued,  which  being  foreign 
to  our  present  subject,  we  shall  not  stop  to  describe. 
We  will  only  state  that  in  some  establishments  the  pro- 
cess of  liquation  is  adopted;  in  others  amalgamation  is 
used ;  while  in  others  again,  the  metal  is  roasted  with 
common  salt  to  form  a  soluble  double  chloride  of  silver 
and  sodium,  from  which  the  silver  is  precipitated  by 
means  of  metallic  copper. 

NAPIER'S  PROCESS. 

The  plan  of  copper  smelting,  patented  by  Napier,  is 
said  materially  to  shorten  the  operation  and  greatly  to 
diminish  its  expense. 

When  Cornish  ores  are  worked  in  this  method,  they 


332  COPPER  SMELTING. 

are  first  thoroughly  calcined  in  an  ordinary  furnace  and 
then  mixed  with  rich  Cobre  ores,  or  other  sulphurets 
rich  in  copper,  in  such  proportions  that  the  iron  and  silica 
may  combine,  and  the  matt  obtained  may  contain  from 
30  to  50  per  cent,  of  copper.  This  mixture  is  fused 
and  skimmed  in  precisely  the  same  manner  as  the  cal- 
cined ore  in  the  second  operation  of  the  regular  process. 
As  soon  as  the  face  of  the  metal  is  cleaned,  a  quantity 
of  soda-ash  or  salt  cake  is  introduced,  and  well  mixed 
with  the  mass.  The  alkaline  sulphuret,  thus  formed, 
dissolves  whatever  antimony,  tin  or  arsenic  may  be 
mingled  with  the  mass,  forming  with  them  soluble  double 
sulphurets.  When  salt  cake  is  used,  about  8  per  cent, 
of  charcoal  is  mixed  with  it,  to  reduce  the  sulphate  of 
soda  to  a  sulphide  of  sodium.  As  soon  as  the  decompo- 
sition is  complete,  which  is  usually  but  a  short  time,  the 
furnace  is  tapped  and  the  matt  cast  into  rectangular 
blocks.  These  are  thrown  as  soon  as  they  have  solidi- 
fied, into  tanks  filled  with  water  in  which  they  crumble 
to  a  fine  powder.  The  water  is  now  siphoned  off  and 
the  sediments  washed  to  disolve  out  the  double  sulphu- 
rets of  antimony,  tin  and  arsenic. 

The  residue  is  calcined  to  complete  oxidation,  an 
operation  which  is  generally  completed  in  24  or  30  hours. 
The  roasted  metal  is  now  mixed  with  coal  or  charcoal 
and  an  additional  quantity  of  ore,  rich  in  silica,  but  free 
from  sulphur  or  arsenic,  and  smelted  in  the  ordinary 
way.  Reduction  takes  place  and  a  slag  is  produced 
which  contains  but  little  copper. 

When  carbonates  of  copper  or  tile  ore,  containing  a 
small  percentage  of  earthy  bases  and  a  large  amount  of 


COPPER  SMELTING.  333 

silica,  are  treated  in  this  way,  the  iron  scales  from  the  roll- 
ing mill  and  forging  hammer  are  added,  in  order  to  form 
a  fusible  slag.  Rich  iron  scoria  or  carbonate  of  iron 
may  be  used  instead  of  the  scales,  but  all  sesquioxides 
must  be  avoided,  as  they  part  with  a  portion  of  their 
oxygen  which  combines  with  the  copper  and  deteriorates 
the  product.  If  the  slags  are  too  stiff,  they  may  be 
lightened  by  the  addition  of  salt  or  quick  lime. 

BRANKART'S  PROCESS. 

Like  Napier's,  this  plan  combines  the  humid  with  the 
dry  treatment.  The  rich  ores  from  South  America  and 
Cuba  are  treated  by  this  method,  at  the  Red  Jacket 
Copper  Works  in  Neath,  Glamorganshire.  The  ore  is 
reduced  to  a  fine  powder,  and  then  roasted  in  a  rever- 
beratory  furnace  till  the  sulphurets  are  oxidized  to  sul- 
phates. The  calcined  ore  is  then  thrown  into  large  vats 
or  tanks  filled  with  water.  In  these  the  sulphates  of 
copper  and  iron  are  dissolved,  the  supernatant  liquor 
siphoned  off  into  other  vats  containing  scraps  of  old  iron 
which  precipitate  metallic  copper.  When  all  the  copper 
is  thrown  down,  the  iron  salt  may  be  crystallized  out  of 
the  mother  liquor  after  suitable  concentration.  The  in- 
soluble residue  is  dried,  mixed  with  a  fresh  proportion  of 
ore  and  again  submitted  to  the  process  of  calcination. — 
The  copper  which  has  been  thrown  down  by  the  iron,  is 
roasted,  fused  and  cast  into  ingots. 

RIVOT  AND  PHILLIP'S  PROCESS. 

The  ore  is  roasted  dead,  that  is  to  the  expulsion  of 
sulphuric  as  well  as  sulphurous  acid,  and  the  consequent 


334  COPPER  SMELTING. 

conversion  of  all  the  sulphurets  into  oxides.  When  this 
has  taken  place,  bars  of  iron  are  introduced,  at  this  high 
temperature,  these  rapidly  oxidate  at  the  expense  of  the 
cupreous  oxide,  and  form  with  the  silica  a  fusible  slag 
which  is  raked  off,  leaving  a  bath  of  metallic  copper. 

The  objections  to  this  process  are  that  it  uses  a  great 
deal  of  metallic  iron,  and  that  it  does  not  accomplish  the 
purification  of  the  copper  if  tin,  arsenic,  or  antimony  are 
found  in  the  ores. 

DAVIES'  PROCESS. 

This  is  applicable  only  to  oxides  and  carbonates  of 
copper  which  contain  no  other  metals  than  iron  and 
manganese.  These  are  mixed  in  such  proportions  that 
the  silica  of  the  ores  may  be  to  these  oxides  as  five  to 
seven.  If  silica  be  in  excess,  oxide  of  manganese  is 
added,  and  if  this  oxide  or  that  of  iron  be  superabundant 
more  silica  is  introduced.  The  whole  being  well  mixed 
with  coal,  is  then  smelted  to  produce  the  metal. 

BIRKMYRE'S  PROCESS. 

Copper  pyrites  is  the  ore  treated  according  to  this 
method.  After  being  finely  powdered  and  mixed  with 
nitrate  of  soda,  it  is  placed  in  trays  and  introduced  into 
kilns  resembling  those  commonly  employed  for  roasting 
pyrites.  While  exposed  to  the  heat,  it  is  repeatedly 
stirred  with  a  rake  in  order  to  bring  every  particle  of  it 
within  the  influence  of  the  air  that  passes  through  the 
furnace.  The  nitrate  of  soda  assists  the  atmosphere  to 
oxidate  the  sulphur  and  its  metallic  bases,  and  the  re- 
sult of  the  operation  when  effectually  performed  is  a 


COPPER  SMELTING.  335 

mixture  of  the  sulphates  of  iron,  copper  and  soda,  with 
undecomposed  silicates.  The  soluble  salts  are  leached 
out  and  the  copper  precipitated,  as  in  Napier's  process, 
bj  means  of  metallic  iron. 

DE  SUSSEX'S   PROCESS. 

The  patentee  directs  that  the  ores  be  so  mixed  as  to 
contain  about  sixty  per  cent,  of  silica.  Should  there  be 
more  than  this,  fluor  spar,  lime  or  any  other  substance 
which  will  form  fusible  compounds  with  it,  is  added. 
Twenty-five  pounds  of  finely  burned  charcoal,  or  of 
stone  coal  free  fronr-sulphur,  for  every  five  hundred- 
weight of  mixed  ore  are  then  incorporated  with  the 
charge,  and  the  whole  introduced  into  a  reverberatory 
furnace.  In  three  or  four  hours,  most  of  the  sulphur 
will  be  expelled,  but  to  effect  its  entire  separation,  the 
temperature  is  to  be  lowered,  and  about  five  per  cent,  of 
alumina,  magnesia  or  magnesian  limestone,  or  if  these 
cannot  be  had,  of  nitrate  of  potassa,  soda,  or  lime  to  be 
intimately  mixed  with  the  charge.  The  heat  is  then  in- 
creased to  decompose  sulphate  of  copper.  The  roasted 
ore,  mixed  with  an  equal  weight  of  anthracite  coal,  and 
four  parts  of  silicate  of  potash  or  soda  for  every  ten  parts 
of  silica  in  the  substance,  is  then  melted  to  obtain  the 
metal.  The  patentee  suggests,  if  the  roasting  be  insuffi- 
cient to  expel  all  the  sulphuric  acid,  the  remaining  sul- 
phate of  copper  be  decomposed  by  digestion  in  a  tank  of 
ammoniacal  water,  which  must,  of  course,  contain  exactly 
enough  ammonia  to  decompose  the  unknown  quantity  of 
copper  salt. 

The  whole  plan  is  curiously  unpractical. 


adb  COPPER  SMELTING. 

LOW'S  PROCESS. 

This  is  another  method  which  could  not  be  carried  on 
by  ordinary  workmen  with  any  reasonable  prospect  of 
success.  The  patentee  proposes  to  employ  a  mixture  of 
peroxide  of  manganese,  42  parts ;  plumbago,  8  parts ; 
nitrate  of  potassa,  soda,  or  lime,  2  parts ;  wood  charcoal, 
or  anthracite,  14  parts.  While  the  fusion  for  matt  is 
going  on,  25  pounds  of  this  mixture  are  added  and  rab- 
bled thoroughly  with  the  molten  mass.  The  slag  which 
rises  is  skimmed  off,  and  a  fresh  quantity  of  the  flux 
added,  and  the  same  operation  repeated  till  the  workman 
considers  that  the  copper  has  advanced  sufficiently  to  be 
tapped  out  for  reduction  in  the  smelting  furnace. 

OTHER   PATENTED    PROCESSES. 

Parkes  recommends  that  the  mineral  be  roasted  till  a 
matt  called  close  regule  is  formed,  when  iron  is  added  in 
the  proportion  of  a  hundred  weight  to  each  two  and  a  half 
tons  of  the  above  compound.  The  heat  is  then  urged  so 
as  to  keep  the  whole  mass  in  perfect  fusion  for  some 
time,  and  the  metal  is  finally  tapped  out  as  pimpled  cop- 
per. He  also  suggests  the  use  of  the  refining  process 
previous  to  poling,  but  it  is  objectionable  on  account  of 
the  probable  bad  effects  of  its  oxide  on  the  furnace  bot- 
toms. 

Trueman  and  Cameron  roast  their  sulphates,  boil  the 
calcined  ore  in  a  solution  of  caustic  potash  for  six  hours 
to  separate  the  tin,  arsenic  and  antimony.  The  residual 
ore  is  again  roasted  to  produce  an  oxide  which  is  mixed 
with  a  fresh  portion  of  crude  ore  in  the  proper  propor- 
tion to  convert  all  its  sulphur  into  sulphurous  acid.  The 


COPPER  SMELTING.  337 

silica  should  be  so  proportioned  to  the  iron  as  to  form 
with  the  oxide  of  that  metal  a  fusible  slag,  and  either  sand 
or  cobbing  must  be  added  if  silica  be  deficient.  The  mix- 
ture is  fused  in  quantities  of  two  and  a  half  tons  for  every 
charge.  Five  hours  after  charging,  the  mass  is  well  rab- 
bled, then  allowed  to  rest,  the  slags  being  skimmed  as  they 
rise  to  the  surface.  Another  charge  is  then  introduced 
and  treated  in  the  same  manner,  the  furnace  being  tapped 
only  at  every  second  charge.  This  yields  a  rich  sulphu- 
ret  of  copper  free  from  iron,  which  furnishes  copper  of 
good  quality  when  calcined  and  fused  in  the  reducing 
furnace. 

A  second  patent,  granted  to  Trueman  in  1852,  pro- 
poses to  treat  the  ores  with  an  acid,  and  to  precipitate 
copper  from  this  solution  with  lime  or  its  salts. 

FRENCH    METHOD  OF    COPPER  SMELTING. 

We  have  spoken,  in  a  previous  part  of  this  work,  of 
the  ores  of  Chessy,  near  Lyons.  They  are  red  and 
blue,  the  former  an  oxide,  the  latter  a  carbonate  of  cop- 
per, mixed  with  a  greater  or  less  proportion  of  impuri- 
ties. The  red  ores  contain  from  38  to  76,  the  blue  from 
20  to  26  per  cent,  of  metallic  copper.  The  impurities 
consist  of  susquioxide  of  iron  and  compounds  of  silica 
and  alumina. 

The  furnace  in  which  these  ores  are  smelted  is  called 
by  the  French  fourneau  a  manche.  Its  base  is  made  of 
very  solid  masonry,  strengthened  by  transverse  bars  of 
iron.  The  cavity  is  lined  with  a  coating  of  very  refrac- 
tory material,  cemented  to  the  masonry  in  the  form  of 
an  ellipse,  and  renewed  every  season.  The  two  lateral 
29 


338  COPPER  SMELTING. 

faces  are  constructed  of  gneiss,  and  the  front,  called  fier- 
vende,  of -rectangular  iron  plates,  coated  with  fire-clay. 
The  cavity  is  a  rectangular  parallelepiped  about  six  feet 
long,  five  and  a  quarter  broad,  and  three  and  a  quarter 
deep.  The  sole  is  formed  of  a  fire-brick  made  from 
Bourgogne  clay  and  pulverized  quartz.  The  tuyere  has 
an  orifice  three  inches  in  diameter,  its  muzzle  being 
wrought  and  its  bed  cast  iron.  Opposite  it  is  a  platform 
made  of  clay  firmly  beaten,  in  which  there  is  dug  a  crucible 
on  a  level  with  the  sole  of  the  furnace.  It  is  coated  with 
a  mixture  of  clay  and  finely  powdered  charcoal,  and 
from  it  passes  an  inclined  canal  leading  to  the  receiver 
in  which  the  fluid  collects. 

The  ore  is  mixed  so  that  its  average  content  of  copper 
shall  be  about  27  per  cent.  To  this  is  added  5  per  cent, 
of  lime  and  some  scoria.  Every  hour,  200  pounds  of 
this  mixture  mingled  with  150  pounds  of  coke  are  thrown 
into  the  furnace.  As  the  fusion  goes  on,  the  melted 
metal  and  slag  flow  out  together  into  the  crucible,  when 
the  slag  is  skimmed  off.  As  soon  as  the  metal  fills  the 
basin,  it  is  run  into  the  receptacle.  A  little  water 
sprinkled  over  the  surface  of  the  metal  causes  the  forma- 
tion of  a  skin  or  crust  which  is  removed  from  the  bath. 
The  continued  repetition  of  this  process  converts  the 
entire  bath  into  round  cakes  about  an  inch  thick.  The 
metal  is  run  off  from  the  crucible  twice  in  twenty-four 
hours,  and  the  entire  daily  product  is  about  fourteen 
hundred  weight, 

The  slags  differ  in  their  composition  according  to  their 
color  or  to  the  source  from  which  they  are  taken.  A 
little  scoria  unavoidably  runs  over  into  the  receiver,  and 


COPPER  SMELTING.  339 

this  differs  from  that  which  is  skimmed  from  the  cruci- 
ble in  containing  no  lime.  It  is  essentially  a  silicate  of 
iron  mixed  with  a  little  sulphur  and  other  impurities, 
containing  about  4.5  per  cent,  of  copper,  together  with 
a  little  metallic  iron.  It  is  formed  by  the  action  of  the 
air  upon  the  metals  of  the  bath,  and  the  subsequent  re- 
action of  the  oxides  upon  the  silicious  matter  of  which 
the  receiver  is  composed.  This  corrosion  renders  ne- 
cessary the  repeated  renewal  of  the  walls  of  the  recepta- 
cle, which  must  be  repaired  weekly.  The  slags  which 
are  skimmed  from  the  crucible  are  of  three  colors,  blue, 
black  and  red.  Of  these  the  blue  contain  the  least  ox- 
ide of  copper,  and  are  formed  when  lime  is  present  in 
due  proportion.  The  black  slags  contain  more  copper, 
and  are  produced  when  lime  is  deficient,  or  when  black 
slag  from  a  previous  operation  has  been  added  in  too 
great  quantity.  Red  slags  are  silicates  of  iron  and  cop- 
per, and  are  formed  when  the  silica  is  not  properly  pro- 
portioned to  the  earthy  bases,  or  when  the  heat  is  too 
high,  melting  the  slags  before  the  carbon  has  time  to 
reduce  the  suboxide  to  metallic  copper.  In  the  first  in- 
stance, these  scoria  are  converted  into  the  black  variety 
by  the  addition  of  lime ;  in  the  second  it  is  only  neces- 
sary to  reduce  the  temperature  of  the  furnace. 

The  black  copper  obtained  from  this  furnace  varies  in 
composition.  That  from  which  the  black  slags  have  been 
taken  contains  from  7  to  8  per  cent,  of  iron.  Like  all 
copper  obtained  from  blast  furnaces,  in  every  instance 
it  is  more  or  less  contaminated  with  iron.  The  different 
layers  or  discs,  which  have  been  removed  from  the  same 
bath  vary  in  their  composition,  the  lower  strata  being 


340  COPPER  SMELTING. 

richer  in  copper  on  account  of  the  greater  specific  gravity 
of  that  metal. 

The  average  composition  of  this  black  copper,  as 
determined  by  the  means  of  several  analysis  by  M. 
Margerin,  is  stated  in  the  following  table : 

f.          wsrfit*  9!?J  fcrt«  ,-ite 

Copper,  .         .,*.. 

T    rr  •» 

Iron,        ....         •    .  |af      v  .         .       .. 

T>  'J  /•    T 

Protoxide  of  Iron,  ..  n  •-  .  J  .  . 
Silica,  .  ""I.1''1  j.  '"  .  .  .  .  . 
Sulphur,  .  ^1 ?OV'  ' 

T 

SS'  -      '  i  'ft 

100.00 

This  copper  is  refined  in  a  spleiss-ofen,  which,  together 
with  the  process,  will  be  presently  described. 

SMELTING   OF    THE   MANSFELD    COPPER   SCHISTS. 

The  copper  schists  of  Mansfeld  are,  as  we  have 
already  said,  poor  in  copper,  but  their  great  abundance 
enables  the  metallurgist  to  extract  that  metal  from  them 
with  profit  to  himself.  The  process  adopted  is  very 
ingenious,  advantage  being  taken  of  the  bituminous 
matters  diffused  throughout  the  mass. 

The  first  operation  is  the  calcination  of  the  ore  in 
mounds  containing  each  about  a  hundred.  The  broken 
shales  are  interstratified  with  wood,  and  the  combustion 
is  carried  on  partly  by  this  fuel  and  partly  by  the  bitu- 
men of  the  slate.  These  heaps  continue  burning  fifteen  or 
twenty  weeks,  at  the  end  of  which  time  the  carbonaceous 
matters  are  consumed,  much  of  the  sulphur  expelled  as 


COPPER  SMELTING.  341 

sulphurous  acid  and  the  metals  generally  oxidated.  The 
calcined  ore  is  friable,  yellowish-gray,  and  about  one- 
tenth  lighter  than  it  was  before  the  operation.  In  the 
Lower  Harz,  the  heaps  are  so  arranged  as  to  collect  and 
preserve  the  sulphur. 

The  calcined  ore  is  mixed  with  from  six  to  twenty  per 
cent,  of  fluor  spar,  some  slag  (containing  copper)  ob- 
tained from  a  previous  operation,  and  some  copper  schist 
containing  carbonate  of  lime.  An  ordinary  charge  con- 
tains twenty  hundredweight  of  ferruginous,  fourteen 
of  calcareous  and  six  of  argillaceous  copper  schist, 
mixed  with  three  of  fluor  spar  and  three  of  rich  slag. 
The  time  of  working  this  is  about  fifteen  hours,  and 
the  product  about  one-tenth  of  its  weight  of  copper 
matt,  containing  from  thirty  to  forty  per  cent,  of  me- 
tallic copper. 

The  other  metals  present  in  the  ores,  nickel,  cobalt 
and  silver,  together  with  zinc  and  iron,  are  found  in  this 
matt  in  the  state  of  sulphides.  The  subsequent  treat- 
ment of  this  matt  depends  upon  the  quantity  of  copper 
it  contains.  When  rich,  it  is  roasted  five  or  six  times 
and  then  smelted  into  black  copper.  When  it  contains 
no  more  than  twenty  or  thirty  per  cent,  of  copper,  the 
cakes  of  matt,  alternated  with  brushwood,  are  roasted 
three  successive  times  in  kilns,  the  product  being  turned 
over  after  each  calcination.  The  charge  in  this  instance 
weighs  three  tons,  and  the  operation  occupies  four 
weeks.  The  next  process  consists  in  the  fusion  of  this 
roasted  matt  in  a  cupola,  the  result  being  a  rich  product 
called  spurstein,  containing  from  fifty  to  sixty  per  cent, 
of  copper.  This  is  mixed  with  material  from  the  first 
29* 


342 


COPPER  SMELTING. 


smelting,  and  roasted  six  times  consecutively  during  a 
period  of  seven  or  eight  weeks.  The  fuel  consists  of 
brushwood  and  charcoal,  which  are  interstratified  with 


BLAST    FCRNACB. 
6  6.     Exit  openings. 


ELEVATION. 


BLAST   FURNACE. 
A.  Shaft. 


the  matt,  the  air  being  admitted  to  the  lower  part  of  the 
mass  by  channels  opening  inwardly  at  the  bottom  of  the 
kiln.  The  kiln  is  built  of  stone,  and  consists  of  six 


COPPER  SMELTING.  343 

compartments,  so  arranged  that  the  charge  in  one  of 
them  shall  not  mix  with  that  in  the  adjoining  one.  The 
process  is  a  continuous  one,  the  roasted  matt  of  the  first 
compartment  being  introduced  into  the  second,  with  the 
same  arrangement  of  brushwood  and  charcoal,  then  into 
the  third,  and  so  on  till  the  process  is  fully  completed 
in  the  sixth.  The  gahrrost,  as  the  Germans  call  the 
resulting  product,  resembles  in  color  red  copper  ore, 
with  an  occasional  bluish-gray  tint.  It  is  brittle  and 
contains  some  reduced  copper  as  well  as  sulphate  and 
oxide  of  that  metal.  To  separate  the  sulphate,  it  is 
lixiviated  in  a  descending  series  of  vats,  so  arranged 

Fig.  13. 


BLAST    FURNACE. 
B  B,  basins,  6  tap-door,  c  c  channel  to  conduct  metals  to  furnace,  1 1  tuyeres. 

that  the  solution  drawn  off  from  one  shall  pass  through 
the  next  below  in  regular  succession,  till  it  becomes  so 
concentrated  that  it  can  be  crystallized  with  very  little 


344  COPPER  SMELTING. 

evaporation.  Sometimes  this  process  is  carried  on  after 
each  roasting  in  the  compartments  of  the  kiln  pro- 
ducing the  gahrrost.  The  calcined  and  lixiviated  matt 
is  generally  melted  with  one-fourth  its  weight  of  lixiviated 
matt  from  the  first  fusion,  and,  when  this  is  of  good 
quality,  one-sixth  to  one-tenth  its  weight  of  rich  copper 
slags,  with  sufficient  charcoal  and  coke.  This  mixture 
is  smelted  in  the  cupola  furnace  in  quantities  of  three 
or  four  tons,  the  operation  occupying  twenty-four  hours. 
The  results  are  hlack  copper  and  slags  of  variable  rich- 
ness ;  the  metal,  owing  to  its  greater  specific  gravity, 
sinking  to  the  bottom  of  the  crucible,  and  being  removed 
in  cakes,  as  before  described.  The  slag  is  subsequently 
roasted  with  matt  and  smelted  to  extract  its  copper. 
The  black  copper  is  by  no  means  pure,  since  it  contains 
the  various  metals  already  mentioned  as  present  in  the 
ore.  Of  these,  silver  being  the  most  important,  is  sepa- 
rated by  a  special  process. 

This  is  usually  what  is  known  by  the  name  of  liquation, 
though  sometimes  the  precious  metal  is  separated  from 
the  gahrrost  by  amalgamation.  The  process  of  liquation 
depends  upon  the  low  fusion-point  of  an  alloy  of  silver 
with  lead  or  zinc.  Three  parts  of  the  black  copper  are 
fused  with  ten  or  twelve  parts  of  lead  or  an  equivalent 
proportion  of  litharge  rich  in  silver.  The  alloy  is  run 
into  moulds,  where  it  is  rapidly  cooled  by  water,  and 
lifted  out  in  discs  of  an  inch  or  less  in  thickness.  These 
are  then  placed  on  the  hearth  of  a  furnace  of  peculiar 
construction,  and  heated  gradually.  The  melting  point 
of  the  lead  alloy  being  far  below  that  of  copper,  the 
silver-lead  flows  out  and  is  collected.  When  no  more 


COPPEE  SMELTING. 


345 


oozes  from  the  cakes,  these  are  transferred  to  another 
furnace  where  they  are  subjected  to  a  higher  heat,  by 
which  more  silver  is  recovered  and  the  cakes  left  in  a 
purer  state.  They  still,  however,  contain  a  little  silver 
and  some  lead,  but  the  latter  metal  is  entirely  removed 
in  the  subsequent  operation  of  refining. 

The  refining  is  carried  on  either  in  a  spleiss-ofen 
(split-hearth  furnace)  or  in  the  arrangement  figured 
below.  The  spleiss-ofen  is  a  furnace  of  peculiar  con- 
struction, consisting  of  a  sole  communicating  by  sepa- 
rate channels  with  two  basins  into  which  the  copper 
flows.  These,  the  split-hearths,  are  connected  with  one 
another  by  a  canal.  The  channels  leading  from  the 


Fig.  14. 


Fig.  15. 


REFINING  FURNACE. 

a  Crucible,     c  Iron  curb  to  prevent  waste 
of  charcoal,  d  Charcoal  for  slag,  t  Tuyeres. 


SUCTION  OF  REFINING  FURNAGE. 
Crucible,     t  Tuyeres. 


main  hearth  are  provided  with  fire  bricks  to  contract 
them  till  the  discharge  of  metal  is  allowed.  The  main 
hearth  is  elliptical  in  form,  eight  feet  long  by  six  and 
a-half  wide,  and  is  made  of  a  mixture  of  coal-dust  and 
clay  well  beaten  into  a  clay  bottom,  resting  upon  a  bed 


346  COPPER  SMELTING. 

of  brick-work,  the  whole  being  supported  by  a  slag  bot- 
tom built  on  a  foundation  of  gneiss.  Two  tuyeres, 
through  which  the  blast  from  the  bellows  is  thrown, 
complete  the  arrangement.  The  charge  for  this  fur- 
nace, amounting  to  sixty  hundredweight,  consisting  of 
black  copper  mixed  with  granular  copper  and  copper  of 
cementation,  is  introduced  through  the  working-door 
and  spread  over  the  sole  of  the  furnace.  As  soon  as  it 
has  melted,  the  bellows  begin  to  play  over  the  surface 
of  the  bath.  Soon  a  layer  of  cinders  and  scoria  collects 
upon  the  face  of  the  metal.  This  is  skimmed  off.  A 
second  and  third  layer  follow,  and  each  is  skimmed  off 
as  soon  as  it  forms.  When  no  more  slag  is  formed,  the 
fire  is  increased  and  the  liquid  begins  to  boil,  continuing 
to  do  so  for  three-quarters  of  an  hour  or  an  hour,  after 
which  it  remains  tranquil  although  the  heat  be  kept  up. 
In  about  three-quarters  of  an  hour  after  the  boiling  has 
ceased,  the  refining  is  finished ;  the  furnace  is  then 
tapped  and  the  charge  received  in  the  basin.  At  this 
time  a  reddish  mist  hovers  over  the  surface.  This  is 
composed  of  extremely  small  globules  revolving  with 
great  velocity  upon  their  axes.  They  are  composed  of 
a  nucleus  of  pure  metal  covered  with  a  layer  of  pro- 
toxide. The  Germans  collect  them  and  use  them  as 
sand  for  letters.  The  copper  is  removed  in  disks  by 
sprinkling  water  upon  the  surface  and  lifting  off  the 
cooled  layer.  It  is  known  in  commerce  as  rosette 
copper. 

The  liquated  copper  is  treated  in  a  furnace  of  simple 
construction.  It  consists  of  a  hemispherical  crucible, 
sixteen  inches  in  diameter,  rendered  fire-proof  by  a 


COPPER  SMELTING.  347 

coating  composed  of  two  parts  of  powdered  charcoal 
and  one  of  fire-clay,  into  the  cavity  of  which  open  the 
tuyeres.  When  it  is  used,  the  crucible  is  first  filled 
with  lighted  charcoal,  then  more  fuel  is  introduced,  and 
with  it  pieces  of  black  copper  which  are  deposited  oppo- 
site the  tuyere.  The  blast  is  gradually  admitted,  and 
as  soon  as  the  metal  of  the  first  charge  has  been  fused, 
another  supply  of  the  black  copper,  mixed  with  sufficient 
charcoal  to  effect  the  reduction,  is  put  in.  This  process 
of  repeated  charging  is  continued  till  the  crucible  is  full. 
The  slag  which  is  formed  during  this  process  flows  out 
through  a  channel  provided  for  it  into  a  receiver,  where 
most  of  the  copper  it  contains  settles  to  the  bottom. 
As  soon  as  the  crucible  is  full,  the  copper  is  tested  by 
introducing  an  iron  proof-rod  and  withdrawing  a  scale 
of  metal,  which  is  immediately  immersed  in  cold  water. 
When  the  assay  is  brownish-red  on  the  outside,  copper- 
red  within,  thin  and  brittle,  the  refining  is  considered 
finished.  The  blast  is  then  cut  off,  and  the  iron  and 
slag  raked  from  the  surface  of  the  metal,  which  is  re- 
moved in  the  usual  way  with  the  aid  of  cold  water,  till 
the  whole  charge  is  converted  into  rosettes. 

The  charge  for  an  ordinary  furnace  of  this  kind  is 
two  and  a-quarter  or  two  and  a-half  hundredweight, 
though  larger  furnaces  will  work  up  seven  hundred- 
weight. In  the  first  instance,  the  refining  occupies 
three-quarters  of  an  hour,  while  in  the  second  two  hours 
are  required.  The  object  of  the  process  is  to  oxidate 
the  more  readily  scorified  metals,  lead,  iron,  nickel,  &c., 
and  to  run  them  off  in  the  slag.  This  is  not  fully 
accomplished,  as  the  refined  copper  always  retains  ap- 


348  COPPER  SMELTING. 

preciable  quantities  of  these  impurities.  The  slags  vary 
in  color  at  the  different  steps  of  the  operation.  At  first 
they  are  greenish,  containing  much  oxide  of  iron  but 
little  copper.  Towards  the  close  of  the  operation,  how- 
ever, they  become  heavier  and  assume  a  deep  red  color, 
owing. to  the  presence  of  suboxide  of  copper.  These 
are  of  course  worked  over  again  in  the  process  for 
obtaining  black  copper. 

These  rosettes  are  never  pure  enough  for  making 
rolled  copper.  They  are  accordingly  submitted  to  an- 
other operation,  which  consists  in  melting  them  under 
cover  of  charcoal  to  absorb  their  excess  of  oxygen. 
Tests  are  frequently  taken  and  the  process  is  continued 
till  the  full  malleability  is  obtained.  When  the  action 
of  the  charcoal  has  been  so  prolonged  as  to  form  a  car- 
buret, the  bath  is  uncovered  and  the  bellows  compelled 
to  play  over  it,  in  order  to  burn  off  the  excess  of  carbon 
as  carbonic  acid. 

Copper  is  sent  to  market  in  various  forms,  the  most 
common  of  which  is  the  ingot.  Bean  and  feathered 
shot  are  obtained  by  pouring  the  refined  metal  into  an 
iron  perforated  ladle  placed  over  water.  If  the  water 
be  hot,  the  copper  assumes  the  form  of  rounded  grains 
which  are  known  as  bean  shot;  if  it  be  cold,  the  drop- 
pings of  metal  jvill  be  flattened,  irregular  and  branching, 
and  to  these  has  been  given  the  name  of  feathered  shot. 
Japanned  copper  is  made  by  casting  the  refined  in  small 
ingots,  which  are  thrown,  while  quite  hot,  into  cold  water. 
By  this  treatment,  the  metal  acquires  a  fine  red  coating 
of  suboxide  which  gives  it  value  in  the  eyes  of  the  ori- 
entals to  whom  it  is  exported  from  England. 


CHAPTER  VI. 

ALLOTS   OF   COPPER. 

THE  alloys  of  copper  are  both  numerous  and  valuable. 
The  great  majority  of  all  the  alloys  in  common  use  con- 
tain copper  as  a  principal  ingredient.  In  the  following 
description  of  these  compounds,  brevity  is  aimed  at ; 
those  which  possess  merely  scientific  interest  will  be 
only  glanced  at  or  entirely  neglected. 

With  the  metals  of  the  alkalies  and  of  the  alkaline 
earths,  copper  forms  alloys  not  often  met  with.  Potas- 
sium and  sodium  have  been  thought  to  increase  the 
malleability  of  copper.  Dumas  describes  an  alloy  of 
this  kind  composed  of  copper  99.12,  potassium  0.38, 
calcium  0.33  and  iron  0.17  in  the  hundred  parts. 

That  copper  combines  with  aluminium  has  long  been 
known,  for  alumina  has  been  obtained  from  some  varie- 
ties of  commercial  copper.  The  recent  researches  of 
Sainte-Claire  Deville  have  given  us  a  more  definite 
knowledge  of  these  substances.  Some  of  these  alloys 
are  light,  hard  and  white,  others  yellow.  Very  small 
proportions  diminish  materially  the  malleability  of  alu- 
minium, communicate  to  it  a  blueish  tinge  and  render  it 
liable  to  blacken  by  exposure  to  the  air.  On  the  other 
hand,  small  proportions  of  aluminium  harden  copper 
without  materially  affecting  its  malleability,  and  give  it 
the  color  of  different  varieties  of  gold.  By  combining 
30 


850  ALLOYS  OF  COPPER. 

100  parts  of  copper  with  10  of  aluminium,  an  alloy  is 
obtained,  harder  than  that  used  for  money,  malleable, 
resembling  in  color  the  pale  gold  of  the  jewelers  and 
taking  a  brilliant  polish.  The  alloy  of  100  parts  of 
copper  with  5  of  aluminium  is  softer,  approaches  more 
nearly  in  tint  to  pure  gold,  and  is  also  susceptible  of  a 
high  polish. 

With  manganese  and  cobalt,  copper  also  forms  alloys 
under  favorable  circumstances.  Iron  is  difficult  to 
alloy  with  it,  and  generally  renders  it  brittle  and  coarse 
in  the  grain.  I  have,  however,  made  an  alloy  of  copper 
and  iron  which  was  quite  malleable.  Cast  iron  is  ren- 
dered brittle  by  copper.  I  recently  received  for  analy- 
sis a  cast  iron  containing  copper  which  was  so  brittle 
that  it  was  easily  reduced  to  powder  in  a  common  iron 
mortar.  Binman  recommends  a  mixture  of  100  parts 
of  gray  cast  iron  with  5  of  copper  as  a  suitable  material 
for  anvils,  on  account  of  its  hardness. 

With  arsenic,  copper  forms  a  white  alloy,  sometimes 
used  for  thermometer  and  barometer  scales,  dials,  &c. 
It  is  composed  of  9  parts  of  copper  and  1  of  arsenic. 
To  attain  this  proportion,  however,  it  is  necessary  to 
introduce  3J  parts  of  the  latter  metal  before  fusion, 
which  operation  is  conducted  under  salt,  in  a  closed  cru- 
cible. 

The  most  important  of  all  the  alloys  of  copper  are 
those  which  it  forms  with  zinc,  tin,  lead  and  nickel ;  arid 
these  we  now  proceed  to  describe  under  their  commercial 
titles. 

Brass. — This  is  an  alloy  of  considerable  antiquity, 
though  not  so  old  as  bronze.  The  first  writer  who 


ALLOYS  OF  COPPER.  351 

speaks  distinctly  of  it  is  Aristotle.  In  the  time  of  Au- 
gustus, cadmia  is  spoken  of,  and  we  are  informed  that 
it  was  used  in  the  manufacture  of  aurichalcum,  as  brass 
was  called. 

Though  all  alloys  of  copper  and  zinc  are  known  by  the 
generic  name,  brass,  yet  there  are  numerous  varieties 
which  have  received  different  names.  Almost  every 
variety  of  tint  between  the  red  of  copper  and  the  white 
of  zinc,  can  be  communicated  to  these  alloys  by  the 
modification  of  the  properties  of  the  two  metals  employ- 
ed. Although  the  metals  named  are  the  only  essential 
constituents  of  brass,  yet  this  alloy  often  contains  others, 
added  for  some  real  or  fancied  improvement  in  working, 
or  accidentally  present  from  impurities  in  the  constitu- 
ents. Lead,  tin  and  antimony  are  the  most  common  of 
these  foreign  bodies.  Iron  is  sometimes  present  and  is 
always  injurious.  It  does  not  combine  chemically  with 
the  alloy  except  in  very  minute  proportions,  but  is  found 
disseminated  through  the  mass  in  small  magnetic  parti- 
cles. It  makes  the  alloy  hard  and  dull,  diminishes  its 
tenacity  and  malleability,  and  renders  it  liable  to  tarnish 
and  rust  when  exposed  to  the  air.  The  source  of  this  con- 
tamination may  be  either  the  calamine  from  which  brass 
is  often  made,  or  the  old  brass  which  is  melted  over. 

Tin  and  lead  are  not  so  injurious.  Their  presence  is 
even  considered  beneficial  in  some  particulars.  They 
usually  come  from  old  brass  which  has  been  tinned  or 
soldered,  or  from  rosette  copper,  from  which  the  lead, 
employed  to  separate  the  silver  by  liquation,  has  not 
been  completely  separated  in  the  subsequent  process  of 
refining.  "  This  brass,  although  it  is  harder  and  more 


352  ALLOYS  or  COPPEK. 

brittle  than  the  ordinary  kind,  is  more  easily  worked 
under  the  lathe,  but  that  which  is  dry  is  generally  pre- 
ferred by  the  turner ;  it  may  be  welded  together,  and 
the  junction  is  not  easily  broken  ;  in  addition,  it  can  be 
cut  with  a  chisel,  sawn,  and  penetrated  with  exactness."* 
The  following  table  expresses  the  composition  of  several 
varieties  of  this  kind  of  brass.  No.  1  is  a  cast  of  brass 
of  uncertain  origin ;  2  the  plate  brass  of  Jemappes ;  3 
the  sheet  brass  of  Stolberg,  near  Aix-la-Chapelle ;  4 
cast  brass  of  Stolberg : 

1  2  3  4 

Copper, 61.6  64.6  64.8  65.8 

Zinc 35.3  33.7  32.8  31.8 

Lead, 2.9  1.4  2.0  2.2 

Tin, 0.2  0.2  0.4  0.2 

100.0     100.0     100.0     100.0 

The  proportions  generally  thought  to  produce  the 
finest  brass,  are  63  of  copper  to  32  of  zinc.  These  are, 
however,  continually  varied  in  practice  as  may  be  seen 
by  the  foregoing  analyses.  Sometimes  the  variation  is 
the  result  of  accident,  though  it  is  frequently  made  in- 
tentionally, with  a  view  of  providing  for  some  particular 
contingency.  "  Thus,  when  a  rich  alloy  of  considerable 
tenacity  is  required,  the  zinc  is  reduced  to  25  per  cent., 
while  with  one  of  little  resisting  power,  50  per  cent,  of 
zinc  may  be  used,  and  should  a  hard  and  very  brittle 
compound  be  desired,  the  zinc  is  raised  to  60  per  cent."f 

Gilding  metal  is  more  variable  in  its  composition, 
though  resembling  in  the  main  the  variety  just  described. 

*  Muspratt's  Chemistry,  i.  535,  article  COPPER.  f  Ibid. 


ALLOYS   OF  COPPER. 


It  should  be  very  close-grained  and  compact,  so  that 
none  of  the  gold  will  be  obscured  by  the  shining  through 
of  a  duller  metal.  The  following  table  sufficiently  ex- 
presses the  varying  composition  of  this  alloy : 


Copper,  . 

Zinc,    .  . 

Tin,      .  . 

Lead,  .  . 


1 

2 

3 

4 

5 

63.  TO 

64.45 

78.48 

78.84 

82.3 

33.55 

32.44 

17.22 

17.31 

17.5 

2.50 

0.25 

2.87 

0.96 

0.2 

0.25 

2.86 

1.43 

2.87 

0.0 

100.00       100.00       100.00        100.00       1QP.O 


The  densities  of  Nos.  \  and  2  are  8.395  and  8.542  re- 
spectively, and  they  are  considered  by  D'Arcet  to  be 
the  best  adapted  to  the  purposes  of  the  jeweler.  The 
quantity  of  copper  is  often  increased  to  90  or  95  per 
cent.,  when  the  composition  is  analogous  to  chrysocolla, 
and  is  known  as  gilding  metal.*  The  other  brasses  in 
the  table  resemble  Bath  metal,  pinchbeck,  similor  and 
Mannheim  gold. 

Although  lead  and  tin  do  not  deteriorate  the  varieties 
of  brass  we  have  just  been  considering,  they  would  be 
seriously  detrimental  to  those  which  are  to  be  hammer- 
ed, rolled  or  drawn,  did  they  occur  in  large  quantities. 
The  following  table  expresses  the  results  of  several  analy- 
ses of  brass  wire.  No.  1  is  English  brass  wire ;  2  Augs- 
burg wire;  3  wire  made  at  Neustadt-Ebenwald,  near 
Berlin : 

*  According  to  analysis,  the  composition  of  cbrysocolla  is : 
Copper,      .     .     .     90.0 
Zinc,     ....       7.9 
Lead,     ....       1.6 


30* 


354  ALLOYS  OF   COPPER. 

12345 

Copper,     ....  70.29  71.89         70.16  66.2           67.0 

Zinc, 29.26  27.63         27.45  33.0           32.0 

Lead, 0.28  0.20  0.5 

Tin, 0.17  0.85           0.79  .08 

Antimony,    ...  .05 


100.00       100.37          98.60         100.0         100.0 

Malleable  brass  or  yellow  metal,  intended  to  work  well 
under  the  roller  or  hammer,  should  approach  as  nearly 
as  possible  to  the  constitution  of  70  of  copper  to  30  of 
zinc.  The  sheet  brass  of  Romilly  contains,  by  analysis, 
70.1  of  copper  and  29.9  of  zinc. 

The  brass  used  for  machinery  and  locomotives  in  Eng- 
land is  composed  according  to  the  following  table : 

Copper,  .  .  .74.5 
Zinc,  ....  25.0 
Lead,  ...  0.5 

100.0 

Its  fracture  is  of  a  fine  yellow  color,  but  its  mallea- 
bility is  inferred  to  those  varieties  in  which  the  propor- 
tion of  zinc  is  smaller. 

The  usual  manner  of  expressing  the  composition  of  an 
alloy  among  brass  founders,  is  to  name  simply  the  zinc, 
the  quantity  of  copper  being  always  taken  as  a  pound. 
The  following  descriptions  of  the  composition  of  different 
varieties  of  brass  will  be  given  in  this  method  rather 
than  the  centesimal. 

TRUE  BRASS  is  formed  of  two  parts  of  copper  and  one 
of  zinc,  but  in  this  as  in  all  the  other  alloys  of  copper 


ALLOYS   OF  COPPER.  355 

and  zinc,  more  of  the  inferior  metal,  owing  to  its  greater 
volatility,  must  be  added  in  order  to  obtain  this  propor- 
tion. Muntzs  metal  is  made  with  10§  ounces  of  zinc 
to  the  pound  of  copper,  his  sheathing  with  from  9  to  16 
ounces,  according  to  Muspratt.  Bristol  brass,  and  those 
varieties  generally  which  bear  soldering,  contain  less 
zinc.  The  formula  for  Bristol  brass,  given  by  Muspratt, 
is  6  ounces  of  zinc  to  the  pound  of  copper. 

When  cTirysocolla  is  formed,  or  when  it  is  desired  to 
give  the  brass  the  property  of  casting  well,  from  an 
eighth  to  a  half  ounce  of  zinc  is  alloyed  with  each 
pound  of  copper.  The  two  metals,  however,  are  not 
alloyed  directly,  but  the  result  is  obtained  by  fusing  4 
ounces  or  less  of  brass  with  a  pound  of  copper.  Gilding 
metal  is  made  in  the  same  manner,  so  as  to  obtain  the 
proportion  of  an  ounce  or  an  ounce  and  a  quarter  to  the 
pound. 

Princes  metal,  or  Prince  Rupert's  metal,  contains 
about  equal  parts  of  the  two  metals.  Mannheim  gold 
contains  3  or  4  ounces  of  zinc  to  the  pound.  It  is  said 
to  be  made  by  melting  separately  3  parts  of  copper 
and  1  of  zinc,  and  then  suddenly  incorporating  them 
by  stirring.  Red  brass,  or  tombaJc,  as  it  is  called  by 
some,  has  a  great  preponderance  of  copper,  containing 
from  5  ounces  of  zinc  down  to  J  ounce  of  zinc  to  the 
pound.  At  Hegermuhl,  11  parts  of  copper  are  alloyed 
with  2  of  zinc  to  make  a  red  brass,  which  is  afterwards 
rolled  into  sheets.  At  Niirnberg,  Dutch  foil  is  made 
from  a  similar  alloy.  Pinchbeck  is  made  of  2  parts  of 
copper  and  1  of  yellow  brass.  Similor  is  made  of  28 
parts  of  copper,  12  of  yellow  brass,  and  3  of  tin.  Bath 
metal  consists  of  32  parts  of  copper  and  9  of  zinc. 


356  ALLOYS  OF  COPPER. 

Brass  solder,  or  hard  solder,  is  made  by  melting 
together  2  parts  of  brass  with  1  of  zinc,  and  a  little  tin. 
When  the  solder  is  required  to  be  very  strong,  as  for 
brass  tubes  that  are  to  be  drawn,  one-third  less  zinc  is 
used.  The  platin  of  the  Birmingham  button-maker  is 
made  of  8  parts  of  brass  and  5  of  zinc.  Cast  white 
metal  buttons  are  made  of  32  parts  of  brass,  4  of  zinc, 
and  2  of  tin.  Mosaic  gold,  according  to  the  specifica- 
tions of  Parker  &  Hamilton's  patent,  consists  of  100 
parts  of  copper  to  52  or  55  of  zinc. 

Brass  may  be  made  either  by  the  direct  combination 
of  the  pure  metal,  or  by  the  action  of  copper  on  a  mix- 
ture of  zinc  ore  and  charcoal  at  a  sufficiently  high  tem- 
perature. The  latter  method  is  by  far  the  most  ancient, 
and  by  it  brass  was  made  long  before  metallic  zinc  was 
known.  When  an  ore  of  zinc  is  employed,  it  should  be 
free  from  sulphur  and  from  silicate  of  zinc,  and  should  also 
be  well  calcined  in  order  to  facilitate  the  reduction  of 
the  metal.  To  accomplish  this,  the  calamine  is  roasted 
in  heaps,  alternate  layers  of  ore  and  charcoal  being 
erected  into  a  mound,  the  base  of  which  is  composed  of 
billets  of  wood.  It  is  then  ground,  sifted  and  mixed 
with  charcoal.  The  pots  which  are  to  be  used  in  the 
manufacture  are  first  heated  in  a  furnace,  then  the  mix- 
ture of  calamine  and  charcoal  is  introduced  into  them, 
and  the  necessary  quantity  of  rosette  or  grain  copper 
forced  into  the  mixture  by  a  few  blows  of  a  mallet  or 
hammer.  The  surface  is  then  covered  with  a  layer 
of  the  mixture,  the  pots  returned  to  the  kiln  and  sur- 
rounded with  fuel.  The  furnace  is  now  closed,  and  the 
heat  kept  up  for  six  or  seven  hours,  at  the  end  of  which 


ALLOYS   OF   COPPER.  357 

time,  the  contents  of  the  pots  are  at  a  white  heat.  At 
the  close  of  this  period  the  heat  is  pushed,  till  the  fumes 
of  volatilizing  zinc,  indicating  the  reduction  and  fusion  of 
this  metal,  make  their  appearance.  The  heat  is  now 
diminished  to  prevent  the  too  rapid  melting  of  the  copper, 
and  to  ensure  the  thorough  mixture  of  the  two  metals. 
For  three  or  four  hours  the  heat  is  nicely  regulated, 
at  the  end  of  which  time,  the  combination  is  complete. 

The  first  result  of  this  fusion  is  arcot,  a  brass  contain- 
ing less  than  the  standard  proportion  of  zinc.  This  is 
again  fused  with  an  additional  quantity  of  charcoal 
mixture  to  make  the  ordinary  commercial  brass. 

The  other  method  possesses  advantages  over  the  one 
just  described.  By  fusing  the  metals,  not  only  are  fuel 
and  labor,  but  a  larger  product  is  obtained  in  a  given 
time.  This  method  of  direct  fusion  is,  however,  attended 
with  difficulties.  Not  the  least  of  these  is  the  great 
affinity  of  zinc  for  oxygen,  in  consequence  of  which  it 
not  only  loses  its  power  of  combining  with  copper,  but 
is  rapidly  volatilized,  causing  considerable  loss.  For  this 
reason,  the  operator  is  compelled  to  employ  much  larger 
proportions  of  zinc  than  he  wishes  to  have  in  his  fin- 
ished alloy.  This  loss  may  be  diminished  by  covering 
the  surface  of  the  metallic  bath  with  suitable  fluxes,  and 
thus  preventing  this  unfavorable  action  of  the  atmos- 
phere. Lord  Rosse  is  said  to  have  made  the  greatest 
improvements  in  this  direction.  By  deepening  the  kiln 
and  keeping  the  surface  of  the  bath  constantly  covered 
with  a  layer  of  powdered  charcoal  two  inches  thick,  it 
is  pretended  the  loss  of  zinc  is  not  more  than  0.56  per 
cent,  or  Tj<j-  of  the  entire  amount  of  that  metal. 


358  ALLOTS  OF  COPPER. 

How  great  this  loss  usually  is  may  be  learned  from 
Holzapffel's  careful  experiments.  His  loss  was  about 
the  thirtieth  of  the  whole  alloy.  He  fused  twenty-four 
pounds  of  copper,  and  then  gradually  introduced  twelve 
pounds  of  zinc.  The  surface  of  the  metal  was  then 
covered  with  glass  and  left  until  the  contents  of  the  pot 
were  in  perfect  fusion.  The  alloy  thus  obtained,  instead 
of  33^  of  zinc,  contained  only  31  £.  On  remelting  the 
alloy,  it  continued  to  lose  zinc,  till  after  the  sixth  opera- 
tion that  metal  was  reduced  to  4f  ounces  to  the  pound. 

The  specific  gravity  of  brass  is  greater  than  the  mean 
density  of  its  constituents.  Sheet  brass  varies  from 
8.52  to- 8.62;  brass  wire  from  8.49  to  8.73. 

GERMAN  SILVER. — This  alloy  has  been  known  by 
various  names,  as  British  plate,  Argentan,  Cuivre  blanc, 
Maillechort,  Neusilber,  Weisskupfer,  &c.  It  is  an  alloy 
of  copper  with  nickel  and  other  metals.  The  Chinese 
have  long  used  it  under  the  name  of  pakfong,  or  white 
metal,  but  in  Europe  it  has  only  been  known  for  the 
last  hundred  years.  It  was  first  made  in  Germany,  by 
smelting  ore  found  at  Hilburghausen,  near  Sahl,  in 
Henneberg.  Referstein's  analysis  of  the  original  com- 
pound gave  the  following  results : — 

Copper, 40.4 

Nickel, 31.6 

Zinc,  .         .       .  25.4 

Tin, 2.6 


100.0 
The  Chinese   pakfong   always  contains  iron,  which 


ALLOYS   OF   COPPER.  359 

gives  a  brighter  color  to  the  alloy  and  renders  it  more 
compact,  though  it  also  makes  it  hard  and  brittle. 
Nickel  being  rather  a  raw  metal,  attempts  have  been 
made  to  diminish  it  by  substituting  zinc  for  it.  These 
are  successful  only  when  the  zinc  is  limited  to  a  cer- 
tain point,  beyond  which,  if  any  be  added,  the  compound 
though  looking  well  at  first,  assumes  the  hue  of  pale 
brass.  The  following  table,  copied  from  Muspratt,  ex- 
presses the  composition  of  the  varieties  of  this  alloy: — 

1  23  4  56  7  8  9  10         11 

Copper,  .  43.8  40.4  53.4  50.0  6.5.4  60.0  67.0  59.2  550  51.6  45.7 
Nickel,..  15.6  31.6  17.5  18.7  16.S  20.0  20.0  14.8  20.6  25.8  34.3 

Zinc, 40.6      25.4      29.1      31.3      13.4      20.0      20.0      26.0      24.4      22.6      20.0 

Iron, 26      3.4      

Lead, 3.0      

100.0     100.0     100.0     100.0     100.0    100.0     100.0     100.0    100.0     100.0    100.0 

Numbers  1  and  2  are  analyses  of  Chinese  pakfong, 
the  latter  being  very  superior  in  color  and  taking  a  high 
polish.  Nos.  3  and  4  are  alloys,  prepared  by  Frick, 
resembling  a  silver  about  18  carats  fine.  They  are  hard, 
but  tough  and  ductile,  and  become  soft  by  immersing  in 
cold  water.  No.  5  is  Maillechort,  made  in  Paris.  It  is 
quite  malleable  and  takes  a  high  polish  when  heated ;  it 
loses  twelve  per  cent,  and  becomes  whiter.  Nos.  6  and 
7  are  alloys  recommended  by  Gersdorff  of  Vienna,  the 
first  for  forks  and  such  articles,  the  second  for  such 
objects  as  require  soldering.  No  8  is,  according  to  Mr. 
Topping,  of  London,  the  commonest  of  German  silver, 
fit  only  for  wire  and  articles  of  inferior  value.  If  the 
quantity  of  nickel  is  brought  much  below  this,  the  alloy 
will  be  little  better  than  pale  brass,  and  will  tarnish 
rapidly.  The  same  authority  highly  recommends  No.  9, 


360  ALLOYS   OF  COPPER. 

as  being  very  beautiful,  and  little  inferior  to  silver  that 
is  nearly  standard.  No.  11  is  the  richest  alloy  that  can 
be  made  without  injuring  the  mechanical  properties  of 
the  metal. 

Tutenag  is  an  alloy  in  frequent  use  among  the 
Chinese.  It  is  very  fusible,  but  hard,  and  not  easily 
rolled,  and  therefore  answers  better  for  castings.  Its 
composition  is — 

Copper, 40.7 

Nickel, 17.4 

Zinc, 36.9 


100.0 

This  alloy  is  prepared,  like  brass,  in  pots  or  crucibles, 
and  much  of  the  zinc  is  lost.  The  only  way  in  which 
the  bad  effects  of.  this  can  be  obviated,  is  by  taking  a 
larger  quantity  of  the  volatile  metal,  to  allow  for  the 
waste.  The  metals  are  usually  stratified  in  the  crucibles, 
the  lowermost  and  topmost  layers  being  copper,  and  the 
whole  being  covered  with  charcoal  powder  or  pulverized 
glass.  When  fused,  the  metals  should  be  thoroughly 
incorporated  by  stirring  with  a  porcelain  rod.  When 
fragments  of  German  silver  are  fused  a  second  time, 
more  zinc  must  be  added  ia  order  to  make  up  the  loss 
just  alluded  to. 

BRONZE. — This  compound  is  essentially  an  alloy  of 
tin  and  copper,  though  other  metals  are  introduced  in 
practice.  It  is  one  of  the  oldest  known  alloys.  The 
so-called  copper  tools  found  in  Egyptian  quarries,  which 
have  elicited  so  much  ignorant  admiration  from  anti- 


ALLOYS  OF  COPPER.  361 

quarians,  are  in  reality  composed  of  tempered  bronze. 
The  ancient  swords  were  made  of  this  alloy.  A  sword 
found  in  the  peat  moss  of  the  Somme,  contained  of  cop- 
per 87.47,  tin  12.53.  Another,  found  near  Abbeville, 
was  composed  of  85  copper  to  15  tin,  and  another  of  90 
of  copper  to  10  of  tin.  The  bronze  springs  of  the  balistae 
contained  97  of  copper  and  3  of  tin. 

The  application  of  this  compound  to  the  casting  of 
statues,  also  dates  from  a  very  remote  antiquity.  It 
was,  however,  first  brought  to  something  like  perfection 
by  Theodorus  and  Roecus,  of  Samos,  about  seven  hun- 
dred years  before  the  Christian  era.  In  the  reign  of 
Alexander  of  Macedon,  the  celebrated  artist,  Lysippus, 
gave  a  new  impulse  to  this  department  of  art,  by  his 
improvements  in  moulding.  He  made  six  hundred 
bronze  statues  of  his  great  patron,  and  this  wholesale 
manufacture  gave  rise  to  Pliny's  sneer — "  The  mob  of 
Alexander."  Colossal  statues  were  afterwards  made 
from  this  same  metal,  the  most  celebrated  of  these  be- 
ing the  well  known  Colossus  of  Rhodes.  Some  idea 
may  be  formed  of  the  great  demand  for  bronzes,  from 
the  fact  that  the  Roman  Consul,  Mutianus,  found  three 
thousand  bronze  statues  at  Athens,  eight  thousand  at 
Rhodes,  and  as  many  at  Olympia  and  Delphi,  though 
from  the  latter  place  a  great  number  had  been  removed 
before  his  arrival. 

It  must  not  be  supposed,  however,  that  the  ancients 
possessed  the  skill  of  the  moderns  in  the  management 
of  this  metal.  Having  no  means  of  ascertaining  with 
certainty  the  actual  composition  of  these  alloys,  they 
could  not  provide  against  the  oxidation  of  the  tin,  and 
31 


<ib2  ALLOYS  OF  COPPER. 

consequent  refining  of  copper,  which  is  one  of  the  great 
difficulties  in  the  working  of  this  alloy.  Consequently, 
analysis  has  shown  that  their  bronzes  are  of  very  vari- 
able composition,  some  of  them  containing  the  proper 
quantity  of  tin,  and  others  being  nearly  pure  copper. 

Indeed,  this  difficulty  has  not  always  been  overcome 
in  modern  works.  The  statue  of  Desaix,  in  the  Place 
Dauphine*,  and  the  great  column  in  the  Place  Vendome, 
are  signal  instances  of  failure  in  this  respect.  On  ana- 
lyzing, separately,  specimens  taken  from  the  bas-reliefs 
of  the  pedestal  of  this  column,  from  the  shaft,  and  from 
the  capital,  it  was  found  that  the  first  contained  six  per 
cent,  of  tin,  the  second  much  less,  and  the  third  only 
0.21  per  cent.,  being  nearly  pure  copper.  Hence,  it 
appears  that  the  unskilful  founder  had  gone  on  refining 
the  copper  by  the  oxidation  of  the  tin  until  he  had  ex- 
hausted his  copper,  and  that  he  had  then  worked  up  the  re- 
fuse scoriae  in  the  upper  part  of  the  column.  The  cannons 
which  the  government  furnished  him  were  composed  of 
Copper,  .  .  .  89.360 
Tin,  ....  10.040 
Lead,  ....  0.102 

Silver,  zinc,  iron,  and  loss,        0.493 

100.000 

The  moulding  of  the  several  bas-reliefs  was  so  badly 
done  that  not  less  than  seventy  tons  of  bronze  was  re- 
moved by  the  chisellers  employed  to  repair  the  faults. 

Bronze  is  more  fusible  than  copper,  and,  as  in  the 
last  described  alloy,  its  density  is  greater  than  the  mean 
of  its  constituents.  This,  however,  does  not  appear 
when  the  specific  gravity  is  taken  of  bronze  in  bulk, 


ALLOYS   OF  COPPER.  363 

since  its  vesicular  structure  interferes  with  the  accurate 
estimation  of  its  density.  For  this  reason,  the  experi- 
ment must  be  performed,  not  upon  a  solid  piece  of  the 
alloy,  but  upon  its  fine  powder.  Some  of  its  forms  are 
malleable,  especially  that  composed  of  eighty-five  parts 
of  copper  and  fifteen  of  tin.  Other  varieties,  made  of 
different  proportions  of  the  constituent  metals,  may  ac- 
quire malleability  by  tempering,  which  lessens  their 
density  and  hardness,  and  sometimes  renders  them  more 
tenacious.  The  following  table  exhibits,  at  a  glance, 
the  effect  of  this  process  upon  different  bronzes : 

Composition  of  alloy— Copper, 95      90       85      80      75 

Tin,  6       10       15       20       25 

100     100     100     100     100 

Density  before  tempering 7.92  8.08  8.46  8.67  8.57 

after          "                7.S9  8.00  8.35  8.52  8.31 

Hardness  before  tempering, 100  100  100  100  100 

"          after        "              99  98  96  92  91 

Sample  %  line  in  thickness,  before  tempering,  tenacity,      80  66  48  50  70 

after         "               "             100  100  100  100  100 

Sample  8  lines  thick,  before  tempering,  tenacity,          .      100  100  80  80  100 

"        "         "          after           "              "                   .        75  78  100  100  35 

We  have  already  alluded  to  the  difference  made  in 
samples  of  bronze  by  the  oxidation  of  zinc.  The  fol- 
lowing table  expresses  the  change  effected  by  a  series  of 
successive  fusions. 

Number  Weight  of 

Composition. 


ons. 

ounces. 

Loss  per  cent. 

Specific  gravity. 

Copper. 

Tin. 

1 

268 

1.2 

8.565 

90.4 

9.6 

2 

236 

1.6 

8.460 

90.7 

9.3 

3 

204 

2.1 

8.386 

91.7 

8.3 

4 

172 

2.5 

8.478 

92.8 

7.2 

5 

140 

2.6 

8.529 

93.7 

6.3 

6 

104 

3.0 

8.500 

95.0 

5.0 

364  ALLOYS  OF  COPPER. 

It  is  not,  however,  only  the  loss  in  weight,  and  the 
change  consequent  upon  the  diminution  of  the  proportion 
of  tin  which  measures  the  deterioration  of  the  hronze. 
There  remains  mingled  with  it  a  greater  or  less  quantity 
of  the  oxidized  metals,  impairing  its  tenacity  and  its  ca- 
pacity for  wear.  This  is  easily  remedied  by  fusing  it  with 
the  necessary  quantity  of  tin  and  some  charcoal,  and,  if 
required,  by  poling  the  bath  as  in  the  refining  of  copper. 

Another  peculiarity  of  bronze,  when  cast  in  sand 
moulds,  especially  if  they  be  large,  is,  that  shortly  after 
casting,  a  jet  of  liquid  metal  flows  out  from  the  interior, 
either  at  the  sides  or  the  upper  surface  of  the  metal. 
It  has  been  suggested,  to  account  for  this  phenomena, 
that  the  first  part  of  the  alloy  which  comes  in  contact 
with  the  walls  of  the  mould,  condenses,  contracts,  and 
displaces  the  new-expanded  molten  metal  within,  which 
exudes  laterally  when  the  pressure  of  the  metal  from 
above  is  very  great,  but  rises,  if  this  weight  is  not  suffi- 
cient to  keep  it  down.  The  escaping  metal  is  richer  in 
tin  than  the  solidified  alloy. 

The  effect  of  introducing  other  metals  besides  tin,  is 
often  beneficial.  Iron  is  thought  to  improve  the  charac- 
ter of  the  alloy,  rendering  it  harder  and  tougher,  as 
well  as  less  fusible.  The  latter  quality  is  an  advantage 
when  casting  in  sand  moulds,  as  such  an  alloy  is  less 
liable  to  the  formation  of  cavities,  since  the  matter  im- 
mediately solidifies  upon  coming  in  contact  with  the 
walls  of  the  moulds,  and  does  not  allow  the  entrance  of 
air  into  the  fluid  mass,  as  takes  place  with  the  ordinary 
bronze.*  Zinc  is  held  to  produce  similar  results,  and 

*  The  iron  is  not  introduced  in  its  pure  state,  as  in  that  case  it  will  not 
combine  with  the  alloy.  It  must  be  added  in  the  form  of  tinned  plate. 


ALLOYS   OF  COPPER.  365 

is  also  thought  to  give  a  fine  bronze  tint,  when  added 
in  the  proportion  of  two  or  three  per  cent,  of  the  entire 
composition.  Lead  is  considered  detrimental  to  bronze, 
because  it  is  so  readily  oxidized  as  to  act  as  a  scorifier 
upon  the  other  metals.  Besides  this,  its  great  specific 
gravity  causes  a  precipitation  of  the  copper  towards  the 
bottom  of  alloy,  producing  irregularities  in  the  casting, 
especially  in  large  works. 

"  For  many  of  the  uses  to  which  bronze  is  applied  in 
the  arts,  its  composition  is  altered;  thus,  for  wheel- 
boxes  or  sockets,  the  alloy  contains — 

Copper,  .  .  80 
Tin,  ...  18 
Zinc,  ...  2 

100 

"  The  fracture  of  this  alloy  is  nearly  white ;  it  has  a 
dry  grain,  and  is  very  hard,  but  still  may  be  worked. 
The  zinc  is  added  with  the  view  of  preventing  cracks, 
which  are  apt  to  form  in  the  casting,  owing  to  the  con- 
traction of  the  alloy  upon  cooling. 

"  Another  alloy  intended  for  a  similar  use,  and  for 
the  collars  of  motive  cylinders,  has  the  following  com- 
position : 

Copper,  .  .  82 
Tin,  ...  16 

Zinc,     ...  2 

100 
81* 


366  ALLOYS  OF  COPPER. 

"  This  is  somewhat  more  malleable  than  the  preceding, 
so  that  when  the  collar  is  being  forced  on  to  its  place, 
it  is  less  liable  to  break. 

"  An  alloy,  when  required  to  resist  powerful  friction 
and  sudden  shocks,  is  made  of  the  annexed  propor- 
tions : 

Copper,  .  .  83.0 

Tin,  .  .  15.0 

Zinc,  .  .  1.5 

Lead,  .  .  0.5 

100 

"  For  pump-boxes,  and  such  articles  as  require  to  be 
brazed  or  soldered,  the  proportions  are — 

Copper,          .         .         87 
Tin,  .         .         12 

Zinc,  .         .  1 

100 

"  This  alloy,  when  broken,  presents  a  reddish  frac- 
ture, with  a  fine  grain.  It  is  malleable,  but  not  suffi- 
ciently so  as  to  answer  for  the  material  of  stop-cocks, 
pump-valves,  and  the  like,  which  are  subject  to  receive 
concussions,  et  cetera,  that  would  endanger  the  safety 
of  the  article,  unless  it  were  sufficiently  pliant  to  resist 
them.  Compositions  of  this  nature  contain — 

Copper,         .         .         88 
Tin,  .         .         10 

Zinc,  .         .          .2 

100 


ALLOYS  OF  COPPER.  367 

"  This  alloy  has  a  fine  grain,  and  is  capable  of  receiv- 
ing a  high  polish ;  it  has  a  rich  red  color."* 

Bronze  for  statues  should  possess  several  qualities. 
It  should  be  capable  of  flowing  into  all  parts  of  the 
mould,  however  minute  ;  it  should  be  hard,  that  it  may 
resist  accidental  blows ;  it  must  be  of  such  a  composi- 
tion as  to  resist  the  action  of  the  weather,  except  to  the 
extent  of  forming  upon  its  surface  that  greenish  coat 
so  much  admired  in  ancient  bronzes,  and  called  patina 
antiqua.  The  brothers  Keller,  the  famous  founders  of 
the  time  of  Louis  XIV.,  are  celebrated  for  their  success 
in  this  kind  of  statuary.  The  following  tables  express 
the  results  of  the  analysis  of  different  statues  from  their 
foundry : 

1.  2.  3.  Mean. 

Copper,  91.30  91.68  91.22  91.40 

Tin,  1.00  2.32  1.78  1.70 

Zinc,  6.09  4.93  5.57  5.53 

Lead,  1.61  1.07  1.43  1.37 

100.00      100.00      100.00      100.00 

The  analysis  of  the  statue  of  Louis  XV.  gave  the 
following  results : 

Specific  gravity,         8.482 

Copper,       .     .     .  82.45 

Zinc,       ....  10.30 

Tin,        ....  4.10 

Lead,      ....  3.15 

100.00 

*  Muspratt,  op.  cit. 


368  ALLOYS  OF    COPPEE. 

The  properties  required  in  medals  resemble  those  just 
mentioned  as  essential  to  statues.  It  should  be  hard 
enough  to  resist  wear  and  tear,  and  yet  should  possess 
the  opposite  property  of  sensitiveness  to  the  die.  The 
art  of  tempering  enables  the  manufacturer  of  medals  to 
combine  these  two  opposite  qualities.  Modern  medals 
are  said  to  be  far  less  able  to  resist  the  oxidizing  agen- 
cies of  the  atmosphere  than  those  of  ancient  coinage. 
The  reason  assigned  for  this  is  that  too  much  copper  is 
used  in  the  modern  works  of  this  kind,  and  this  metal 
is  always  softer  and  more  prone  to  oxidate  than  an 
alloy  made  with  a  proper  amount  of  tin.  The  propor- 
tion of  tin  commonly  used,  varies  from  seven  to  eleven 
per  cent.,  though  this  sometimes  goes  as  low  as  four, 
and  rises  as  high  as  seventeen  per  cent.  The  best  pro- 
portion is  considered  to  be  from  eight  to  twelve  per 
cent.,  and  it  is  said  if  two  or  three  per  cent,  of  zinc  is 
added,  the  bronze  tint  of  the  alloy  is  greatly  improved. 

Medals  are  usually  cast  in  fine  sand,  and  finished 
afterwards  by  striking  them  up  with  a  die.  Many  pre- 
cautions are  requisite  to  success  in  the  process  of  cast- 
ing ;  but  these  belong  rather  to  the  mechanical  than  the 
chemical  department  of  the  subject.  Suffice  it  to  say, 
that  the  sand  must  be  so  arranged  as  to  give  a  sharp 
impression,  and  to  dry  speedily — a  property  that  is  ob- 
tained, in  the  first  instance,  by  sprinkling  the  surface 
upon  which  the  impression  is  to  be  made,  with  finely 
powdered  charcoal — bone-ash  or  slate — and  in  the  sec- 
ond, by  making  the  exterior  of  coarser  sand,  and  having 
the  whole  as  thin  as  possible.  It  is  also  necessary  to  ob- 
viate the  concentration  of  the  casting,  which  sometimes 


ALLOYS  OF   COPPER.  369 

makes  a  difficulty  in  the  subsequent  use  of  the  die.  This 
is  effected  either  by  making  allowance  for  this  contrac- 
tion in  the  mould,  which  is  larger  than  the  die,  by  the 
calculated  amount  of  shrinking.  An  exterior  coating 
of  a  different  metal  has  been  recommended.  Lead 
paper  has  been  suggested ;  but  the  inconveniences  of 
working  it  make  it  impossible  to  use  it.  As  a  substi- 
tute, tinning  the  model  has  been  resorted  to.  The  coat 
thus  deposited,  though  very  thin,  is  yet  sufficient  to 
make  up  for  the  contraction. 

These  precautions  having  been  observed,  the  compound 
metal  is  fused  in  a  small  wind  furnace,  in  crucibles  con- 
taining ten  or  twelve  pounds  each,  and  is  poured  into 
the  moulds  at  such  a  degree  of  heat  as  will  not  injure 
their  outline.  This  is  a  nice  point  to  hit,  and  the  neces- 
sary skill  can  only  be  acquired  by  experience.  If  the 
metal  be  too  cool  it  flows  badly  in  the  mould ;  if  too  hot 
it  acts  upon  the  moisture  of  the  sand,  disengaging  vapors 
which  give  a  blistered,  irregular  appearance  to  the  cast- 
ing. When  it  has  attained  the  proper  degree  of  heat, 
it  is  coated  with  a  smooth  layer  of  oxide,  beneath  which 
the  metal  is  brilliantly  white.  If  the  heat  be  too  feeble, 
the  oxide  on  the  surface  will  be  uneven  and  tarnished ; 
if  it  be  too  high,  the  oxide  will  fuse  and  assume,  like  the 
metal,  a  luminous  appearance. 

The  moulds  having  been  filled,  the  castings  should  be 
removed  as  soon  as  possible  and  thrown  into  water  to 
anneal  them.  After  receiving  the  impression  of  the 
die,  they  are  again  heated  that  they  may  regain  the 
hardness  and  durability  of  bronzes. 

It  is  customary  to  finish  up  the  medals  by  giving 


370  ALLOYS  OF  COPPER. 

them  a  surface  resembling  that  of  ancient  bronzes. 
This  is  effected  by  boiling  them  in  a  solution  of  chloride 
of  ammonium  and  acetate  of  copper.  A  film  of  oxide 
of  copper  is  thus  deposited  upon  the  surface  which  varies 
in  depth  of  color  in  proportion  to  its  thickness.  If  the 
metal  be  rich  in  tin,  this  result  is  not  easily  accom- 
plished ;  but  if  zinc  be  present  the  effect  can  be  easily 
produced  by  rubbing  its  surface  with  a  powder  consist- 
ing of  sand  and  some  copper  salt.  Sometimes  the  fol- 
lowing ingredients,  digested  in  dilute  nitric  acid  are 
used ;  they  must  be  applied  with  the  brush.  Common 
vinegar,  ninety  parts  ;  sal  ammoniac  nine,  and  powdered 
green  one,  will  give  the  color  of  antique  bronze.  For 
Florentine  bronze,  eight  parts  of  alcohol  and  two  of  red 
lead,  are  digested  in  dilute  nitric  acid  and  applied  as 
above.  Another  plan  is  to  dissolve  in  a  quart  of  vinegar 
three-fourths  of  an  ounce  of  sal  ammoniac,  and  one  and 
a-half  drachms  of  binoxalate  of  potash,  (salt  of  sorrel) 
and  to  apply  to  the  bright  surface  of  the  thoroughly 
cleansed  metal  by  rubbing  with  a  soft  rag  or  brush  till 
perfectly  dry.  The  process  must  be  repeated  till  the 
full  effect  is  obtained. 

Dr.  Ure  recommends  for  giving  an  antique  appear- 
ance, a  solution  of  one  part  of  sal  ammoniac,  three  of 
cream  of  tartar,  and  six  of  common  salt  in  twelve  of 
hot  water,  the  whole  to  be  mixed  with  eight  parts  of  a 
solution  of  nitrate  of  copper  of  specific  gravity  1.160. 
"This  compound,  when  applied  repeatedly  in  a  mode- 
rately damp  place  to  bronze,  gives  it  in  a  short  time  a 
durable  green  coat,  which  becomes  by  degrees  very  beau- 
tiful. More  salt  gives  it  a  yellowish  tinge,  less  salt  a 


ALLOYS   OF  COPPER.  371 

bluish  cast.  A  large  addition  of  sal  ammoniac  accele- 
rates the  operation  of  the  mordant." 

Ordnance  or  Cannon  Metal. — This  alloy  is  composed 
of  eighty-eight  or  ninety  parts  of  copper  and  ten  or 
twelve  of  tin,  to  which  proportions  the  founder  generally 
strictly  confines  himself.  The  metals  must  be  absolutely 
pure,  as  the  smallest  quantities  of  sulphur,  lead,  iron  or 
arsenic  would  seriously  impair  the  alloy,  perhaps  to  the 
extent  of  rendering  the  cannon  useless.  Lead,  as  has 
already  been  stated,  renders  bronze  soft  and  diminishes 
its  tenacity,  and  besides  the  fusion  point  of  such  an 
alloy  is  so  low  that  the  heat  developed  by  the  firing  of 
the  piece  would  melt  it  to  such  an  extent  as  to  occasion 
inequalities,  which  would  be  very  dangerous.  Sulphur, 
arsenic  or  iron  would,  of  course,  confer  upon  the  alloy  a 
brittleness  totally  incompatible  with  the  purposes  for 
which  it  is  to  be  employed. 

Furthermore,  the  tin  itself  may  be  used  in  such  pro- 
portions as  to  produce  the  faults  of  over-hardness  and 
want  of  tenacity.  Even  when  these  proportions  are 
exact,  a  practical  difficulty  occurs  in  the  casting,  owing 
to  the  tendency  of  the  metals  to  separate  according  to 
their  specific  gravity.  This  separation  occasions  serious 
defects  in  the  guns,  as  those  portions  of  them  Avhich 
contain  excess  of  tin  and  are  therefore  easily  fusible, 
assimilate  the  sulphur  of  the  gunpowder  and  give  rise 
to  cavities  of  sulphide  of  tin,  which  quickly  occasions 
incrustations.  This  cause  of  defect  is  obviated  by  cool- 
ing the  metal  to  a  certain  point  before  allowing  it  to 
fall  into  the  mould,  and  by  effecting  the  hardening 
within  a  given  time. 

It  has  been  ascertained  that  the  same  proportions  do 


372  ALLOYS  OF  COPPER. 

not  answer  for  all  pieces  of  artillery.  Thus,  eight 
pounders  require  only  seven  and  a-half  per  cent,  of  tin, 
while  twelve  pounders  and  heavier  guns  are  best  made 
of  the  proportions  already  given. 

The  loss  in  these  castings  is  very  considerable,  though 
by  skill  and  care  it  may  be,  in  great  part,  recovered. 
It  is  laid  down  as  a  rule  that  to  obtain  one  hundred 
pounds  in  the  casting,  two  hundred  and  twenty  pounds 
must  be  fused  in  the  furnace.  This  is  distributed  as 
follows : 

Weight  of  casting, 100  pounds. 

Loss  of  bronze  in  the  scoria,        .     .       12J     " 

Bronze  wasted  in  the  debris,  .     .     .     107J     " 

Bronze  employed, 220       " 

Owing  to  this  loss  of  metal  and  temporary  waste  it  is 
evident  that  the  greatest  care  and  skill  are  necessary 
for  the  proper  management  of  the  work.  Rules  have 
consequently  been  given  for  the  proper  proportioning  of 
the  materials  used.  It  is  said  that,  in  each  charge,  one- 
tenth  of  its  weight  of  new  or  ingot  copper  should  be 
used,  and  that  the  tin  in  the  shape  of  ingots  should 
amount  to  fifteen  per  cent,  of  this.  The  following 
quantities  are  required  to  produce  twenty-two  hundred 
pounds  of  casting : 

Ingot  copper,      ....         488  pounds. 

Ingot  tin,    .        ^   fojTjL     v        •    ,       73       " 

Old  pieces  of  bronze,  .."  f,T.      .       1769       " 

Bronze  in  the  waste  attending  the 

manufacture,         .'*       .       '•       2556       " 

Total  weight  of  mixture,      ^-^p-'   4886       " 


ALLOTS   OF  COPPER.  373 

The  real  loss  under  proper  care  does  not  amount  to 
ten  per  cent.,  and  rarely  reaches  this  point,  usually  not 
exceeding  six.  Cornish  or  Banca  tin  is  preferred  as 
being  freer  from  lead  than  most  commercial  tin.  When 
old  tin  is  used,  it  is  absolutely  necessary  that  it  should 
be  subjected  to  a  process  of  refining  before  it  is  intro- 
duced into  the  alloy. 

Bell  MetaL — The  standard  composition  of  bells  is 
seventy-eight  of  copper  and  twenty-two  of  tin,  the  latter 
being  usually  increased  to  compensate  for  the  loss  by 
oxidation.  The  founder,  however,  usually  employs  other 
metals  to  increase  the  fusibility  of  the  alloy,  as  well  as 
its  cheapness.  The  admixture  of  these  foreign  metals 
undoubtedly  impairs  the  quality  of  the  product,  yet  for 
the  reasons  just  mentioned  it  is  customary  to  introduce 
them.  A  common  formula  for  the  manufacture  of  bells 
is  the  following : 

Copper,     .        .       „.  ., ..,..;•      ,  ,  j.»^i    77 

Tin, 21 

Antimony, 2 

100 

The  following  analysis  by  Thomson  shows  the  com- 
position of  English  bell- metal: 

Copper,       ;'^1T  ,'.':'"'*  .^-V-''-      '         80'° 

Tm,    .  /,;,/,'  ;^;.:.f.:;V*    i(u 

Zinc,  .yJv!  ,:,fi,-  „ ..;  B  3i  ;  Jf         •  5'6 

Lead,     .         .         .     .,-  v:;c  • 

100.0 
32 


374  ALLOYS  OF  COPPEK. 

The  founder  also  often  introduces  antimony  and  bis- 
muth in  order  to  give  a  more  crystalline  character  to 
the  alloy  as  well  as  to  impart  a  certain  tone  to  the  bells. 

Berthier's  analysis  of  the  bells  of  the  pendules,  or 
ornamental  clocks,  made  in  Paris,  gave  the  following 
results : 

Copper, 72.00 

Tin,      .      '  .  ':v'u.;  '*'",  '"''V  kv.         26.56 
Iron, 1.44 


100.00 

As  in  the  alloys  previously  described,  so  in  this,  new 
metal  is  not  always  employed.  In  the  working  up  of 
the  old  bell-metals  and  this,  however,  it  is  necessary 
that  their  composition  should  be  accurately  known,  so 
that  the  mean  of  the  alloy  shall  yield  a  bell  of  the 
required  quality.  In  the  preparation  of  the  alloy,  the 
whole  of  the  tin  is  not  put  in  at  the  beginning,  about 
one-third  being  reserved  for  addition  when  the  whole  of 
the  bath  is  in  perfect  fusion.  About  one-tenth  more 
than  the  weight  destined  for  the  bell  must  be  melted, 
this  quantity  being  expended  in  waste  and  scorification 
during  the  process. 

Cymbal  or  Tam-tam  Metal. — Alloys  for  this  purpose 
are  prepared,  as  already  said,  from  seventy-eight  or 
eighty  per  cent,  of  copper  and  twenty  or  twenty-two  of 
tin.  Newly  cast,  the  alloy  of  cymbals  is  grayish  white, 
with  a  fine  close  grain.  It  is  very  brittle  and  less  fusi- 
ble than  bell-metal.  The  full  sonorous  property  of  the 
metal  is  obtained  by  heating  and  sudden  cooling.  The 


ALLOYS  OF  COPPER.  375 

fused  alloy  is  cast  into  moulds,  and  as  soon  as  the 
objects  have  hardened,  they  are  removed  and  heated  to 
a  cherry-red  in  a  furnace.  They  are  then  placed  be- 
tween iron  discs  and  plunged  into  water,  where  they  are 
allowed  to  cool.  They  are  then  sufficiently  tenacious  to 
be  worked  under  the  hammer.  The  instruments,  having 
been  thus  formed,  are  now  heated  and  allowed  to  cool 
slowly  in  the  air.  In  consequence  of  this  treatment 
the  vibrations  of  the  metal  when  struck  are  stronger, 
and  the  sound  they  emit  much  louder. 

Telescope  or  Speculum  Metal—The  standard  of  this 
alloy  is : 

Copper, 66.7 

Tin, 33.3 


100.0 

From  this  standard,  however,  as  in  the  other  alloys, 
there  is  much  deviation  in  practice.  The  color  is  steel- 
white,  the  alloy  is  very  hard,  brittle,  and  takes  a  high 
polish.  As  its  name  implies,  it  is  used  in  the  construc- 
tion of  mirrors  for  telescopes  and  for  other  uses. 

Edwards,  as  quoted  by  Ure,  gives,  in  the  Nautical 
Almanac  for  1787,  the  following  directions  for  making 
speculum  metal : 

"  The  quality  of  the  copper  is  to  be  tried  by  making 
a  series  of  alloys  with  tin,  in  the  proportion  of  one  hun- 
dred of  the  former  to  forty-seven,  to  forty-eight,  to  forty- 
nine,  to  fifty  of  the  latter  metal ;  whence  the  proportions 
of  the  whitest  compound  may  be  ascertained.  Beyond 
the  last  proportion,  the  alloy  begins  to  lose  in  brilliancy 


376  ALLOYS   OF   COPPER. 

of  fracture,  and  to  take  a  bluish  tint.  Having  deter- 
mined this  point,  take  thirty-two  parts  of  the  copper, 
melt,  and  add  one  part  of  crass  and  as  much  silver, 
covering  the  surface  of  the  mixture  with  a  little  black 
flux ;  when  the  whole  is  melted,  stir  with  a  wooden  rod, 
and  pour  in  from  fifteen  to  sixteen  parts  of  melted  tin, 
(as  indicated  by  preliminary  trials,)  stir  the  mixture 
again,  and  immediately  pour  it  out  into  cold  water. 
Then  melt  again  at  the  lowest  heat,  adding,  for  every 
sixteen  parts  of  the  compound,  one  part  of  white  arsenic, 
wrapped  in  a  paper,  so  that  it  may  be  thrust  down  to 
the  bottom  of  the  crucible.  Stir  with  a  wooden  rod  as 
long  as  arsenical  fumes  rise,  and  then  pour  into  a  sand 
mould.  While  still  red-hot,  lay  the  metal  in  a  pot-full 
of  very  hot  embers,  that  it  may  cool  very  slowly,  whereby 
the  danger  of  its  cracking  or  flying  into  splinters  is 
prevented." 

Tinning  Copper. — The  process  of  tinning  copper  is 
really  the  formation  of  an  alloy  upon  the  surface  of  cop- 
per. The  vessel  to  be  tinned  is  heated  to  the  point  of 
fusion  of  the  coating  metal,  excluding  the  air  to  prevent 
oxidation,  and  taking  measures  to  bring  the  surfaces  of 
the  two  metals  in  contact.  Under  these  circumstances, 
combination  takes  place,  provided  no  other  substance  in- 
tervenes, but  as  there  is  usually  a  thin  film  of  oxide  upon 
all  manufactured  copper,  this  must  be  removed.  Sul- 
phuric acid  is  often  employed  for  this  purpose,  but  the 
most  common  agent  is  chloride  of  ammonium.  The  surface 
of  the  vessel  to  be  cleansed  is  sprinkled  with  this  salt  in 
powder,  heat  is  then  applied  and  the  powder  rubbed  over 
the  whole  surface.  The  heat  first  dissolves  and  then 


ALLOYS   OF  COPPER.  377 

volatilizes  the  chloride,  a  portion  of  it  being  decomposed 
to  form  chloride  of  copper  with  the  reduced  oxide.  The 
chloride  is  removed  by  rubbing,  leaving  a  perfectly 
bright,  untarnished  surface.  The  heat  being  still  kept 
up,  tin  is  laid  upon  the  surface,  and  the  operator,  with 
his  pad  or  cork,  rubs  it  over  till  the  combination  is  con- 
sidered complete.  The  amount  of  tin  deposited  was 
found  by  Proust  to  vary  from  one  grain  to  a  grain  and  five 
eighths  for  every  square  inch  of  surface.  The  larger 
quantity  is  made  up  in  part  of  some  tin  which  has  not 
been  alloyed  with  the  copper  but  has  simply  been  solidi- 
fied upon  the  surface.  This  is  of  no  advantage  to  the 
purchaser,  and  being  a  loss  to  the  manufacturer,  it  ought 
to  be  removed.  This  is  easily  accomplished  by  raising 
the  temperature  and  pressing  well  down  with  the  pads, 
when  the  excess  of  tin  will  flow  off. 

Sometimes  an  alloy  of  tin  and  lead  is  used,  on  account 
of  the  greater  fusibility  of  that  compound  and  the  greater 
readiness  with  which  it  is  applied.  This  ought  not  to  be 
used  for  vessels  intended  for  culinary  purposes,  as  a  very 
small  amount  of  lead,  daily  introduced  into  the  system, 
is  sufficient  to  destroy  health  and  life.  Proust,  it  is  true, 
has  made  some  calculations,  based  upon  experiment,  by 
which  he  undertakes  to  show  that  the  amount  of  lead 
dissolved  by  the  acids  of  cooking,  is  very  small,  even  to 
the  extent  of  being  incognizable  to  ordinary  chemical 
reagents,  and  that,  indeed,  the  tin  of  the  alloy  is  alone 
dissolved,  leaving  the  lead  adhering  to  the  vessel  easily 
recognized  by  its  bluish  white  tint.  There  must,  how- 
ever, come  a  time  when  all  the  tin  will  be  dissolved  and 
then  the  lead  will  necessarily  be  attacked. 
32* 


378  ALLOYS  OF  COPPER. 

An  improvement  in  this  process  has  been  suggested 
by  Biberal,  in  which  a  compound  of  tin  and  iron  is 
substituted  for  pure  tin,  the  proportion  of  iron,  in  some 
instances,  rising  as  high  as  one  to  six  of  tin.  The  heat 
must  be  as  high  as  redness  in  order  to  fuse  this  and  keep 
it  melted,  while  it  is  applied  to  the  surface.  The  alloy 
is  applied  by  placing  the  end  of  the  ingot  upon  the  heat- 
ed plate  and  rubbing  briskly  with  some  pressure.  When 
the  whole  has  been  treated,  the  vessel  is  allowed  to  cool 
and  any  excess  or  inequality  in  the  tinning  is  removed 
by  a  scraper.  The  superiority  of  this  application  arises 
from  the  high  degree  of  heat  necessary  to  melt  it,  its 
fusibility,  of  course,  diminishing  with  the  amount  of  iron 
alloyed  with  the  tin. 

Recovery  of  Copper  from  its  Alloys. — Our  account  of 
the  alloys  of  copper  would  be  incomplete,  were  we  to 
omit  to  describe  the  method  by  which  this  metal  may  be 
recovered  from  its  compounds.  Its  separation  from  tin 
depends  entirely  upon  the  greater  oxidability  of  the  lat- 
ter metal.  Fourcroy's  method  of  separation  consisted, 
first,  in  thoroughly  calcining  the  alloy  in  a  reverberatory 
furnace,  and  finely  powdering  the  resulting  oxide.  A 
fresh  quantity  of  alloy  was  then  melted  in  the  same  fur- 
nace, and  to  it  was  added  one  half  its  weight  of  the  oxide. 
The  temperature  was  increased  and  the  mixture  well  in- 
corporated. At  the  end  of  a  few  hours,  copper  nearly 
pure  rested  upon  the  hearth,  and  a  slag  comprising  the 
mixed  oxides  and  some  of  the  earthy  matters  collected 
on  the  surface.  This  was  raked  out  and  the  copper 
tapped  into  proper  moulds.  The  scoriae  were  levigated, 
and  the  metallic  copper  separated  by  elutriation.  By 


ALLOYS  OF  COPPER.  379 

this  process,  50  pounds  of  copper,  containing  only  one 
per  cent,  of  foreign  matter,  were  obtained  from  100 
pounds  of  bell-metal. 

The  washed  scoriae  were  then  intimately  mixed  with 
one  eighth  their  weight  of  pulverized  charcoal,  and  melt- 
ed in  a  reverberatory  furnace.  The  result  was  an  alloy 
of  60  parts  of  copper  and  40  of  tin,  together  with  slags 
richer  in  tin  than  those  of  the  previous  operation.  The 
alloy  thus  obtained  was  roasted  and  melted  in  the  same 
furnace.  The  air  sweeping  over  the  surface  oxidated 
the  tin  more  rapidly  than  the  copper,  and  the  surface  of 
the  metal  was  covered  with  a  coat  of  oxide.  This  was 
skimmed  off  from  time  to  time,  till  the  metal  had  reach- 
ed the  standard  of  bell-metal,  when  it  was  run  out  and 
subjected  to  the  whole  process  again. 

M.  Briant  improved  this  process  by  substituting  eli- 
quation  for  some  of  the  roasting.  By  fractioning  the 
products  flowing  off  during  the  process,  he  obtained, 
firstly,  tin  with  lead ;  secondly,  tin  nearly  pure ;  and 
lastly,  tin  alloyed  with  some  copper.  The  spongy  mass 
which  remained  on  the  sole,  was  treated  by  oxidation. 
By  this  process  he  not  only  incurred  less  loss  of  tin,  but 
also  consumed  less  fuel  and  obtained  purer  products  of 
known  composition,  applicable  directly  to  the  purposes 
of  the  arts. 


APPENDIX. 


STATISTICS    OF    COPPER. 

The  most  interesting  facts  in  regard  to  the  produc- 
tion of  copper  will  now  be  given  in  a  tabular  form. 
The  tables  are  taken  from  "Whitney's  Metallic  Wealth 
of  the  United  States,  altered  by  collation  with  the  tables 
published  in  Muspratt's  Chemistry,  and  continued  from 
the  published  accounts  of  the  ticketings  at  Cornwall  and 
Swansea. 

As  Great  Britain  occupies  so  important  a  position 
among  the  producers  of  copper,  the  statistics  of  her  pro- 
duction are  first  given. 

TABLE    I. 

PRODUCTION  OF  CORNWALL  FROM  1726  TO  1775  INCLUSIVE. 


Years. 

Tons. 

Av'rage  price 
per  ton. 

Amount 

Av'age  amt. 
prod  —  tons. 

Av.  annual 
value. 

1726,1 
1738,  / 

64,800 

£    t.     d. 
1  15  10 

£ 

473,500 

6,480 

£ 
47,250 

1736,1 
1745,  / 

75,520 

786 

560,106 

7,552 

56,010 

1746,1 
1755,/ 

98,790 

780 

731,457 

9,879 

73,145 

1756,1 
1765,/ 

169,569 

766 

1,243,045 

16,970 

124,304 

1766,1 

264,273 

6  14     6 

1,778,337 

26,427 

177,833 

382 


APPENDIX. 


TABLE  II. 

PRODUCTION  OF  CORNWALL  FROM  1771  TO  1857,  TEAR  ENDING  JCNE  30. 


Tears. 

Tons  of  ore. 

Tons  of  cop- 

Value In  pounds 

Standard. 

Percent. 

per. 

Sterling. 

yield. 

1771, 

27,896 

3,347 

189,609 

£81  05.1 

1772, 

27,965 

3,356 

189,505 

81  00 

1773, 

27,663 

3,320 

148,431 

70  00 

12 

1774, 

30,254 

3,630 

162,000 

68  00 

1775, 

•  29,966 

3,596 

192,000 

78  00 

1776, 

29,433 

3,532 

191,590 

79  00  = 

1777, 

28,216 

3,386 

177,000 

77  00 

1778, 

24,706 

2,965 

140,536 

72  00 

1779, 

31,115 

3,734 

180,906 

73  00 

1780, 

24,433 

2,932 

171,231 

83  00 

1781, 

28,749 

3,450 

178,789 

77  00 

12 

1782, 

28,122 

3,375 

152,434 

70  00 

1783, 

35,799 

4,296 

219,937 

76  00 

1784, 

36,601 

4,392 

209,132 

72  00 

1785, 

36,959 

4,434 

205,451 

71  00 

1786, 

39,895 

4,787 

237,237 

75  00. 

1787, 

38,047 

.... 

190,738 



1788, 

31,541 

150,303 

1789, 

33,281 

184,382 

1790, 

1791, 

1792, 

1793, 

1794, 

42,816 

320,875 

1795, 

43,589 

336,189 

1796, 

43,313 

4,950 

356,564 

1797, 

47,909 

5,210 

377,838 



1798, 

51,358 

5,600 

422,633 

1799, 

51,273 

4,923 

469,664 

121  00 

1800, 

55,981 

5,187 

550,925 

133  03 

1801, 

56,611 

5,267 

476,313 

117  05^ 

1802, 

53,937 

5,228 

445,094 

110  18 

1803, 

60,566 

5,616 

533,910 

122  00 

Q  Q 

1804, 

64,637 

5,374 

570,840 

136  05 

o.o 

1805, 

78,452 

6,234 

862,410 

169  16 

1806, 

79,269 

6,863 

730,845 

138  05  > 

1807, 

71,694 

6,716 

609,002 

120  00  " 

1808, 

67,867 

6,795 

495,303 

100  07 

1809, 

76,245 

6,821 

770,028 

143  12 

91 

1810, 

66,048 

5,682 

569,981 

132  05 

.1 

1811, 

66,499 

5,948 

563,742 

126  00 

1812, 

75,510 

7,248 

608,065 

113   00  ; 

APPENDIX. 
TABLE  II.— Continued. 


383 


Years. 

Tons  of  ore. 

Tons  of  cop- 
per. 

Value  in  pounds 
Sterling. 

Standard. 

Per  cent, 
yield. 

1813, 

86,713 

8,166 

685,572 

£113  Qs.-] 

1814, 

87,482 

7,936 

766,825 

128  00 

1815, 

79,984 

6,607 

582,108 

121  00 

1816, 

83,058 

7,045 

541,737 

109  00  ' 

9.5 

1817, 

75,816 

6,608 

422,426 

96  00 

1818, 

80,525 

6,714 

587,977 

121  00 

1819, 

93,234 

7,214 

728,032 

136  00  : 

1820, 

92,672 

7,364 

620,347 

119  00 

1821, 

98,803 

8,163 

628,832 

111  00 

1822, 

106,723 

9,331 

676,285 

104  00  ' 

8.1 

1823, 

97,470 

8,070 

618,933 

110  00 

1824, 

102,200 

8,022 

603,878 

110  00 

1825, 

110,000 

8,417 

743,253 

124  00  : 

1826, 

118,768 

9,140 

798,790 

123  00 

1827, 

128,459 

10,450 

755,358 

106  00 

K  /\ 

1828, 

130,866 

9,961 

759,175 

112  07  ' 

7.y 

1829, 

125,902 

9,763 

725,834 

109  14 

1830, 

135,665 

10,890 

784,000 

106  15 

1831, 

146,502 

12,218 

817,740 

99  18  : 

1832, 

139,057 

12,099 

835,812 

104  14 

1833, 

138,300 

11,185 

858,708 

110  00 

Q  -1 

1834, 

143,296 

11,224 

887,902 

114  04 

O.I 

1835, 

153,607 

12,271 

896,401 

106  11 

1836, 

140,981 

11,639 

957,752 

115  12 

1837, 

140,753 

10,823 

908,613 

119  05 

1838, 

145,688 

11,527 

857,779 

109  03 

1839, 

159,551 

12,451 

932,297 

110  02 

7.8 

1840, 

147,266 

11,038 

792,758 

108  10 

7.5 

1841, 

135,090 

9,987 

819,949 

119  06 

7.4 

1842, 

135,581 

9,896 

822,870 

120  16 

7.3 

1843, 

144,806 

10,926 

804,445 

110  01 

7.5 

1844, 

152,667 

11,247 

815,246 

109  17 

7.4 

1845, 

157,000 

12,293 

835,350 

103  10 

7.8 

1846, 

158,913 

12,448 

886,785 

106  08 

7.8 

1847, 

148,674 

11,966 

830,739 

103  12 

8 

1848, 

155,616 

12,870 

825,080 

97  07 

8.3 

1849, 

144,933 

12,052 

716,917 

92  12 

8.3 

1850, 

150,890 

11,824 

814,037 

103  19 

7.8 

1851, 

154,299 

12,199 

808.244 

101  00 

7.9 

1852, 

152,802 

11,706 

828,057 

106  12 

7.6 

1853, 

180,095 

11,839 

1,124,561 

136  15 

6.5 

1854, 

180,687 

11,779 

1,153,756 



6.6 

1855, 

195,193 

12,577 

1,263,739 



6.8 

1856, 

209,305 

13,275 

1,283,639 



1857, 

289,768 

18,915 

1,816,644 

384 


APPENDIX. 


TABLE    III. 

This  table  gives  the  productiveness  of  the  United  Kingdom  down 
to  1835,  with  accuracy;  from  that  down  to  1848,  the  statement  is  only 
approximate,  as  the  British  copper  cannot  be  certainly  separated  from 
that  of  foreign  origin. 

Tears.  Tons  of  copper.    Tears.  Tons  of  copper. 


1820, 
1821, 
1822, 
1823, 
1824, 
1825,. 
1826, 
1827, 
1828, 
1829, 
1830, 
1831, 
1832, 
1833, 
1834, 


ans  of  copper. 

Tears. 

8,127 

1835, 

10,288 

1836, 

11,018 

1837, 

9,679 

1838, 

9,705 

1839, 

10,358 

1840, 

11,093 

1841, 

12,326 

1842. 

12,188 

1843, 

12,057 

1844, 

13,232 

1845, 

14,685 

1846, 

14,050 

1847, 

13,260 

1848, 

14,042 

14,470 
14,770 
10,150 
12,570 
14,670 
13,020 
12,850 


14,840 
14,900 
14,950 
13,780 
14,720 


The  above  is  taken  from  Whitney,  who  quotes  it  from  G.  R.  Porter's 
Progress  of  the  Nation,  London,  1851. 


TABLE   IV. 

Also   from  Whitney,  expressing  the  productiveness  of  the   new 
srorld,  approximately  in  tons  of  copper. 
Tears.  Chili.  S  America.  Cuba.       U.  S.  &  Canada 


1830, 
1835, 
1840, 
1845, 
1846, 
1847, 
1848, 
1849, 
1850, 
1851, 
1852, 
1853, 
1854, 


0 





700 

9,000 

....      4,500 

.... 

13,270 

....      6,800 

100 

13,800 

....      5,150 

150 

11,850 

....      4,000 

300 

12,275 

....      4,000 

500 

12,450 

....      3,600 

700 



1,200      3,400 

650 

3,400 

900 



2,600 

1,100 



1,300      2,500 

2,000 

APPENDIX. 


385 


Ill 

Years. 

5' 

|| 

li§- 
»|S 

:  :  :  III:  ::§:§:: 

Rnsssia. 

ill 

g-    ^    3 

:::{:::  ::.«::: 

Sweden. 

1| 

^  H  p 

p 

S*  s 

I|.| 

iiiliilfSliiii 

Norway. 

ES* 

O 

3f  3 

s* 

ST  2    ^. 

: 

G.  Britain. 

s3 

p    s  S- 

_    i.,^^ 

^ 

S      O,     <r»- 

•iislsSSIIIS:: 

Prussia. 

o    |    a 
ego 

£3      "• 

:::S:  :::::!!•; 

Hartz. 

1 

§ 

Iff 

:  :  0:  •&:  :  :  HB6:  : 

Saxony. 

Di 
2 

!* 

»  CO  »,,  ,»»»-. 

Austria. 

S 

5 

^^ 

««-—•—«• 

CD 

g  ^ 

II 

I  i  ::::::  S§a8Si 

France. 

c 

J°  1 

:  :  :  :  g:  g:  g:  :  :  :  : 

Spain. 

<s 

e.  8 

S 

^  § 

M  

£ 

^    I 

g  

2, 

N   S 

» 

r 

:  fe:  :  :  :  §:  :::::: 

Turkey. 

^ 

»     g* 

0 

•*, 

g:  r  0;  :  :  • 

Algiers. 

5 

^      S" 

jr] 

o 

I! 

;;;!;!!;;;;  i; 

Asia. 

3 

00 
0 

II 
ig 

iiiiiliil0:    i  ! 

Australia. 

o 

4 

3 

s 

5'  c^ 
g    > 
S  I' 

::§§38g8^i     [: 

N.  Zealand. 

1 

33 


386 


APPENDIX. 


Years. 

1835, 
1840. 
1845^ 
1846, 
1847, 
1848, 


TABLE  VI. 

PRODUCE  OP  CUBA  IN  TONS  OF  COPPER. 
Tons  of  copper.      Yearn. 


681 
4,139 
6,352 
4,092 


3,867 


Tons  of  copper. 

.  3,594 

.  3,239 

.  3,300 

.  2,500 

.  2,200 


TABLE    VII. 

Sales  at  Swansea  in  tons  of  ore  of  2]  cwt.,  specifying  the  country 
in  which  they  were  raised. 


1 
£ 

i 

| 

a 

! 

t 

2 

>H 

1 
1 

1 

X 

eS 

£ 

•= 

i 

1 
o 

I 

! 

CJ 

1 

R 

3 

3 

1S2S, 

3,875        8  510 

199  1 

12,584 

1829, 

6,796 

7,044 

456 

187 

25 

14,508 

1830, 

2,203 

9,115 

733 

201 

12,252 

1831, 

1,982 

9,707 

674 

244 

'*57 

12,664 

1832, 

3,830      11,399 

531 

33 

•  •** 

is 

62 

15,870 

1833, 

2,147      11,293 

624 

435 

... 

14,499 

1834, 

3,713      17,280 

453 

1,107 

517 

23,070 

1835, 

4,038     22,123 

329 

2,342 

4,0>7 

.... 

32,919 

1836, 

2,233     21,013 

1,099 

4.402 

3,106 

20 

"4l9 

32,292 

1837, 

2,395      22,306 

1,277  1     6,'825 

6,405 

14 

39,222 

1838, 

4,374]    22,161 

i,023  1    10,924 

7,725 

*196 

46,403 

1839, 

4,449!    23,613 

479  1      8,436 

15,148 

.... 

29 

52,154 

1840, 

1,277  i    20,166 

55      10,325 

24,831 

140 

3 

57,797 

1841, 

1,885  |    14,321 

38 

10,395 

30,864 

.... 

67 

67,570 

1842, 

2,767  i    15,253 

36 

9,475 

34,562 

69 

250 

62,412 

1843, 

1,889  l    17,600 

11,550 

28,071 

'.'.'.'.          61 

1,057 

60,228 

1844, 
1845, 

2,130 
2,536 

20,063 
19,647 



11,857 
4,755 

33,331 
39,270 

61          10 
1,635        395 

232 

66,684 
68,826 

1846, 

1,684 

17,553 

7,721 

27,279 

3,232       675 

441 

58,485 

1847, 

746 

14,373 

5,795 

21,918 

6,321 

407 

1,259 

50,819 

1848, 

774 

12,633 

4,163 

25,778 

5,891 

121 

49,360 

1849) 

1,677 

9,852 

923 

23,282 

7,552 

307 

43,593 

1850, 

1,574 

10,478 

1,537 

21,591 

4,561 

1,972 

41,713 

1851, 

592 

11,678 



827 

21,692 

2,238 

ai9 

2,502 

39,838 

1852,  I  1,504 

10,104 

89 

892 

16,177 

1,356 

513 

1,019 

31,654 

1853,     2,174 

11,367 

1,203 

14,058 

1,040 

1,046 

2,086 

32,974 

Total,  65,144 

390,652  |  8,095  j  116,554 

399,692 

33,977 

3,609 

12,667 

1,030,390 

APPENDIX. 
TABLE    VIII. 


387 


SALES  AT  SWANSEA  FOR  THE  DIFFERENT  QUARTERS,  FROM  1853. 


1853. 

Quarter  to  March  31, 

"          June    30, 

"          Sept.    30, 

Dec.     31, 


1854. 

Quarter  ending  March  31, 
"  June    30, 

"  Sept.    30, 

"  Dec.     31, 


1855. 

Quarter  ending  March  31, 

"  June    30, 

Sept.    30, 

Dec.     31, 


1856. 

Quarter  ending  March  31, 

"  June    30, 

"  Sept.    30, 

Dec.     31, 


1857. 

Quarter  ending  March  31, 
"  June    30, 

"  Sept.    30, 

"  Dec.     31, 


Tons  of  ore.         Amount  of  money. 


5,119 
8,444 
10,089 
9,332 

32,974 


6,280 
13,200 
11,262 
13.161 

43,903 


11,741 
10,217 
10,761 
9,471 

42,190 


9,976 
9,350 
11,789 
6,542 


£  «.  d. 

91,622  11  6 

115,441  7  6 

123,801  10  6 

146,996  9  0 


477,861  18  6 


7,037  103,838  15  6 

9,708  134,294  2  0 

10,921  145,282  2  6 

9,017  134,691  5  0 


36,683 


518,106  5  0 


94,669  15  0 
199,083  6  6 
171,114  10  0 
189,660  9  0 

654,468  1  0 


186,890  10  0 

150,757  13  0 

148,347  6  6 

142,474  8  0 


169,320  9  6 
143,702  5  0 
172,852  17  0 
89,144  2  6 

575,019  14  0 


The  falling  off  in  this  last  quarter  is  due  to  deficiency  in  receipts 
from  Cuba,  and  to  the  fact  that  smelting  works  have  been  more  ac- 


388  APPENDIX. 

tively  engaged  on  the  west  coast  of  South  America,  as  well  as  to  the 
low  price  of  copper,  and  general  depression  of  business. 

Not  being  able  to  obtain  satisfactory  accounts  of  the  productive- 
ness of  the  Lake  Superior  region,  I  have  not  introduced  any  thing 
concerning  the  mines  of  that  district. 

Of  the  copper  smelting  establishments  of  the  United  States  I  have 
no  statistics. 

Baltimore  turns  out  about  8,000,000  pounds  of  refined  copper  an- 
nually. 


8  8  3  4     5 


UNIVERSITY  OF  CALIFORNIA  AT  LOS  ANGELES 

THE  UNIVERSITY  LIBRARY 
This  book  is  DUE  on  the  last  date  stamped  below 


WAR  13 


Fo 

20>n-l,  '41(1122) 


\ 


IIIJIllllJllHIlllll™ 


PLEASE  DO  NOT  REMOVE 
THIS  BOOK  CARD  ^ 


S 


University  Research  Library 


